#feedback

Correct me if I'm wrong, but I see no "gap" and no reason why answer A isn't 100% correct.

preferable --> comparable & greater heat resistance

comparable or greater heat resistance --> preferable

The stimulus explicitly states: "However, vacuum tubes’ maximum current capacity is presently not comparable to that of semiconductors."

Answer A states: "Vacuum tubes are not now preferable to semiconductors for use in digital circuits."

I think we can forget any information about “small experimental vacuum tubes" because the stimulus refers to ALL vacuum tubes in the last sentence.

This was very helpful for me! However there is a minor flaw in your last contrapositive. You swapped "can live" with "don't live". Your contrapositive should read: "(If you can not live in NYC, then you are not a US Citizen).

Thanks for your help!