Benevolent : Kind :: Unclear : _____________________
Step 1: First pair analysis.
"Benevolent" is synonymous with "Kind."
Step 2: Apply same relation.
So "Unclear" should match with its synonym.
Step 3: Match options.
- (a) Bright → clear, opposite.
- (b) Thick → not exact synonym for unclear in this context.
- (c) Luminous → shining, opposite of unclear.
- (d) Muddy → not clear, obscure → correct synonym. \[ \Rightarrow \boxed{\text{Muddy is the correct synonym for Unclear.}} \]