Letter is a type of Earn. Letter can be used for Marketing. Promotion is part of Marketing. 
Variety is a synonym of Kind. Flavor is a type of Kind. Flavor is related to Preserve. 
Earn <--IsA-- Letter --UsedFor--> Marketing <--PartOf-- Promotion 
Variety <--Synonym--> Kind <--IsA-- Flavor <--RelatedTo--> Preserve 