I'm really struggling with C being correct, and I think it's to do with the word "tend" in the stimulus. Because of this word, I understood the stimulus as "introduction of labour-saving technology...will tend to [but won't necessarily always] undermine the values in that social system". So there's no reason why technology couldn't eliminate economic roles in a society whose values are not susceptible to change.

I went for D, and I now understand why that's wrong so I'm left with C by process of elimination but it still bugs me. Can anyone help?

I agree with Drackedary - if you've already covered Introduction to Logic, you're good to skip ahead to the Logic Games if you're feeling antsy about them :)

Seamus, I was in the exact same position as you - pretty comfortable on RC and LR but couldn't even finish the LG section on time. Trust me: get the basic 7sage package, watch all his videos on logic and then watch his videos on Logic Games. Use his LG technique and I swear you'll be flying through that section like nobody's business. In a week and a half I went from being unable to finish, to nailing the whole section with at least five minutes to spare. It is SO learnable!