The last sentence in the stimulus tripped me up. My mind didn't smoothly translate "avoid a decrease" and "not decrease" into its opposite and then link it to "will decrease" while juggling with necessary condition "only if." I think it is partly because there is the added confusion of the mental pair (decrease vs. increase) going against the pair (decrease vs. not decrease). Difficult question.

I do not see the difficulty that J.Y. indicates in the video. Small vacuum tubes are a subset of all vacuum tubes. If no vacuum tubes allow the capacity of electrical current that is necessary to make them preferred, then the necessary condition fails, game over answer A. Perhaps J.Y. misread "current" capacity as "heat capacity at present."?

This is made easier if one uses Venn diagrams. Put "almonds grown in CA" in the center circle. Then each of the concepts "grown for domestic consumption" and "requiring intense irrigation" have to overlap that circle more than 50%. There necessarily has to be some almonds in the overlapping zone.

It is argued by some that I should spend less money on my girlfriend. But let's look at the real cause of my bankruptcy: My gambling problem. Therefore it is not warranted to say that I should spend less money on my girlfriend.