Question

ever witnessed someone getting bullied and wished there was something you could say or do to brighte their day? now you can. send kindness through an uplifting image or gif, or create and share your own which words from this campaign best indicate the target audience?
\send kindness\
\i am a witness\
\someone getting bullied\
\something you could say\

Explanation:

The campaign is focused on people who have seen bullying and want to support those affected. The phrase "I am a witness" directly refers to the people who have observed bullying, which is the target audience being called to act with kindness. Other options describe actions or the recipients, not the target audience.

Answer:

"I am a witness"