Question

dictionary entry
in·val·i·date /ɪnvæləˌdæt/ verb

1. to make something not true; to prove wrong

example: i will invalidate his untrue story using photos to show what actually happened.
synonyms: disprove, refute, contradict
look at the dictionary entry. which is the correct meaning for invalidate?
to show, to make a presentation
to make something not true, to prove wrong
to cause to be sad, to make discouraged

Explanation:

The dictionary entry clearly defines "invalidate" as "to make something not true; to prove wrong". The example also supports this meaning by showing using photos to prove a story untrue. The synonyms like "disprove" and "refute" further reinforce this definition.

Answer:

To make something not true, to prove wrong