That Shakespeare’s The Winter’s Tale (1610–1611) is modeled after Euripides’ Alcestis (fifth century B.C.) seems undeniable.
Conclusion
Shakespeare probably came to know E's play Alcestis via a Latin translation.
Evidence
Shakespeare knew little to no Greek, so it's unlikely he read the original Greek version of Alcestis.
Evaluate
This is the Curious Fact / Explanation template that shows up so much on Strengthen and Weaken.
Curious Fact: How was Shakespeare exposed to Alcestis? Author's Story: He read a Latin translation
To strengthen a causal argument, we want to 1. Help Author's Explanation or 2. Rule Out Alternate Explanation
Goal
Get rid of four answers that Strengthen (the correct answer may weaken or may just be neutral).
They should either help us believe that Shakespeare learned Alcestis via a Latin translation, or rule out a different way that Shakespeare might have learned Alcestis.