A. strengthens
B. opposes
C. contradicts
D. verifies
confirms : establish the truth or correctness of (something previously believed or suspected to be the case).
strengthens : make or become stronger.
opposes : disagree with and attempt to prevent, especially by argument.
contradicts : deny the truth of (a statement) by asserting the opposite.
verifies : make sure or demonstrate that (something) is true, accurate, or justified.
Antonym of confirms is contradicts