Opt is related to Choose. Choose is related to Best. Best is related to Comparison. Comparison is derived from Compare. 
Sound is a type of Energy. Sound is related to Ear. Ear is a synonym of Attention. 
Opt <--RelatedTo--> Choose <--RelatedTo--> Best <--RelatedTo--> Comparison --DerivedFrom--> Compare 
Energy <--IsA-- Sound <--RelatedTo--> Ear <--Synonym--> Attention 