Tough is a synonym of Dense. Dense is a synonym of Dumb. Dumb is related to People. People can Donate. 
Distinct is related to Bell. Bell is related to Music. 
Tough <--Synonym--> Dense <--Synonym--> Dumb <--RelatedTo--> People --CapableOf--> Donate 
Distinct <--RelatedTo--> Bell <--RelatedTo--> Music 