PT64.S1.Q23 - ethicist: martial vows contain

emilycyoung1

This question is about an ethicist who says love refers to a feeling therefore a marital vow saying to love until death do us part is a promise that makes no sense because feelings are not within our control and a promise to do something not within one's control makes no sense. He concludes that no one should take love in this context to be referring to feelings.
The conclusion follows logically if which is assumed?

The answer choices are:
a: no feelings are within our control
b. People should not promise to something not within their control
c. love can be taken to refer to something other then feelings
d. promises should not be interpreted in a way that makes no sense
e. promises that cannot be kept do not make sense

The answer is D and I can't figure out why. Help.
https://7sage.com/lsat_explanations/lsat-64-section-1-question-23/

DumbHollywoodActor

This is a difficult sufficient assumption question:

Premise: A promise to do something not within one’s control makes no sense.

Premise: Feelings are not within one’s control.

Sub conclusion: If love in a marital vow refers to a feeling, then this promise makes no sense.

Main conclusion: People should not take “love” to be referring to feelings.

Analysis: For the sub-conclusion, we have a pretty good chain set up here.

A→B→C

_
A→C

So, the gap in this argument MUST be between the sub-conclusion and the main conclusion. But that structure is fairly apparent:

A→C

_
/A

So, our SA just needs to negate the necessary condition.

What am I looking for? “The promise makes sense.”

Selection: The only possible answers are (D) and (E). But (E) adds a new concept about keeping promises, something that is entirely irrelevant to the argument. (D) is tricky because it entails a double negative, which essentially means “Promises should make sense”. That plugs the gap in the reasoning and allows the argument to be valid. (D) is the correct answer.