a) False. The inverse of any matrix is denoted by A-1. Putting a negative in the argument corresponds to rotating in the other direction (normally counter-clockwise).
b) True. Definition of linear independence. Check av1+bv2+cv3=0.
c) True. Definition of subspace.
d) If v and w are linearly independent: True.
If v and w are linear combinations of one another (which is not specified): False.