Which of these expressions is not a natural collocation?

1. a delicate scent / fragrance / stink of pine needles
1. scent
2. fragrance
3. stink
2. the rich aroma / odour / scent of freshly ground coffee
1. aroma
2. odour
3. scent
3. the pungent smell / perfume / stench of the fish market
1. smell
2. perfume
3. stench
4. a weak / slight / bitter aftertaste
1. weak
2. slight
3. bitter
5. a faint hint / flavour / aroma of expensive perfume
1. hint
2. flavour
3. aroma
6. the bland flavour / taste / savour of mashed potato
1. flavour
2. taste
3. savour