I agree with many others that this is poorly constructed, but this is my take (as someone who incorrectly answered A).

How to eliminate A:

A states that "regular training" is necessary to keep one's skills a certain level, but it's not strong because it doesn't explain why children's training wouldn't be pointless. With this argument, Parent Q could say, okay - then let them learn those skills as adults.

Why C is correct:

C shows that, no matter what, increasing children's technical skills will be useful for them in the long term. So under Parent Q's framework (advancing tech), any kind of training would still be helpful overall. This does a better job at strengthening because it specifically addresses the issue at hand, which is whether or not children should receive computer training.

Why I still lowkey think the question is bad:

In general, I feel like strengthen/weaken should truly be that only one provides a true flaw or strengthening premise. I think that there is absolutely a world where (A) is the right answer to this question if (C) didn't exist.

My takeaway:

When multiple answer choices can be correct, return to the stem and fully identify the point at issue. The answer that more properly addresses that specific point is likely to be correct.

When the LSAT says something is "enthusiastic" it truly has to be enthusiastic.

In this passage, nativism and cosmopolitanism are depicted as opposing forces by the author. The author explicitly states that this tension has "divided the Hispanic-American consciousness." He doesn't say "We need to embrace both cosmopolitanism and nativism" (which would have led to answer A). He says "we need to reconcile these opposing tendencies" - that kind of implies a different solution altogether, although he believes there are elements necessary of both.

TLDR; I got the answer wrong (A) because I read the MP as "these things are both good" when the actual MP was "these things are in conflict but both have value."

looking for similar advice!! broke through to low 170s and now i live here😭