Question

Which is logically equivalent to ~p -> q?
a.) ~q -> p
b.) ~q -> ~p
c.) q -> p
d.) q -> ~p

Answer 1

I am not certain of your usage of ->, but I have a technique you can use that will work always.

Construct a truth table, such as this:
http://www.gateways2learning.com/SetTheory/EquivalentStatements.pdf

Answer 2

It is just like your previous post. The contrapositive of

~p -> q

reverses the direction of implication, and the logical values:

~(q) -> ~(~p)
~q -> p