Concept:
The word declined means refused, rejected, or chose not to accept something.
Step 1: Understand the meaning of declined.
In the sentence,
She declined to participate.
it means she refused to participate.
Step 2: Analyse the options.
• Supported = encouraged or agreed with
• Avoided = stayed away from
• Opposed = resisted
• Repudiated = rejected
Step 3: Find the opposite.
Since declined means refused, the opposite idea is accepted or supported.
\[
{\text{Supported}}
\]
Hence,
\[
{\text{Option (A)}}
\]