You will be given a trivia clue, and the category it belongs to. You should answer with the best answer that belongs in the category and is described by the clue. For simplicity, answers should be in all lower cased letters.

Q: Category: ANIMALS 
Clue: These mollusks, not oysters, are the most common source for freshwater pearls

A: mussels
****
Q: Category: INTERNATIONAL ROAD VEHICLE STICKERS 
Clue: SGP

A: singapore
****
Q: Category: PEOPLE 
Clue: With Theodore Simon, this French psychologist developed a series of intelligence tests

A:
binet
****