What does tephra mean i'm really confused

Which statement best explains how shakespeare transformed thesource material, hecatommithi by giraldi cinthio? lago is driven by a sense of duty, while ensign is motivatedby jealousyensign's plot only involves the moor, while lago plots to trickcassio, the captainwhile ensign's trickery is driven by his love for the moor'swife, lago's plot is driven by his hatred for cassio and themoorin shakespeare's play, the men are either good or evil bynature, in the source material, they are influenced by outsidesources