The core challenge in this question (as indicated by the stem) is to map out the analogy in a way that makes sense for all the concepts. Here’s the correct mapping:

Cook = Bacteria
Pleasing Guests = Resisting Ingredients
Several Dozen Guests = Herbal Remedies (lots of active ingredients)
Single Guest = Standard Antibiotics (one active ingredient)
________
Analogy: It’s harder for the cook (bacteria) to please (resist) several dozen guests (herbal remedies) than to please (resist) a single guest (standard antibiotics).

Getting all the way here can be pretty difficult because the stimulus’ wording is intentionally thorny (notice that the concept of a Single Meal is a full-on red herring – not important to the analogy at all). In situations like this, scanning for a clear anchor point becomes critical. Here’s one:

For a strain of bacteria, the difficulty of [blah] is like a cook’s difficulty in [blah].

That gives you Cook = Bacteria, which is huge for filling in the rest of the map.

Getting to the full correct mapping of the analogy is really tricky because there’s an alternative mapping that’s (intentionally) much more intuitive unless you flesh it all the way out.

For starters, it’s natural to see the remedies as the cook, thinking the analogy should be about how standard antibiotics and herbal remedies are “cooking up” ingredients to fight the bacteria, which would be the guests.

This alternative map is also supported by the natural reading that a single meal should correspond to standard antibiotics – you know, the thing with just one active ingredient.

But this interpretation breaks down if you try to flesh it all the way out. Here’s the incomplete mapping, with the missing / mismatched pieces underlined:

WRONG MAPPING
Cook = The Remedies
Pleasing Guests = Being Effective Against
Single Meal = Standard Antibiotics
Guests = Bacteria
________
Analogy: It’s harder for the cook (anti-bacterial remedy) to please (be effective against) all of several dozen guests (lots of different bacteria?) with a single meal (standard antibiotics) than to please (be effective against) a single guest (one bacterium?) with one meal (standard antibiotics again?)

So a lot of elements do line up on this (completely natural and intuitive) reading of the analogy. But when you map it out you’re left with a big misalignment between meals and guests.

To make everything match up, you need to make bacteria the cook and map the two remedies onto the different numbers of guests:

CORRECT MAPPING
Cook = Bacteria
Pleasing Guests = Resisting Ingredients
Several Dozen Guests = Herbal Remedies (lots of active ingredients)
Single Guest = Standard Antibiotics (one active ingredient)
________
Analogy: It’s harder for the cook (bacteria) to please (resist) several dozen guests (herbal remedies) than to please (resist) a single guest (standard antibiotics).

Notice that the concept of a single meal doesn’t show up at all on this map. It’s a complete distraction without a counterpart on the other side of the analogy. If the counterpart existed, it would be the idea that bacteria are limited to one method of resistance when trying to resist active ingredients.