Concept:Helena's sadness is caused by Demetrius rejecting her after abandoning the promises he once made to her.
Explanation:The speaker is Helena, and she is thinking about how Demetrius once swore sincerely that he belonged only to her.
He "hailed down oaths" that she alone was his love.
But when Demetrius saw Hermia's eyes, those promises lost all their strength.
Like hail melting under heat, his words dissolved and disappeared.
Demetrius broke his vow and turned his affection fully toward Hermia.
This deep betrayal leaves Helena rejected, hurt, and doubtful about love itself.
Her troubled mood does not come from wanting to punish Hermia, from any meeting with Hermia, or from going into the forest.
It comes purely from being cast aside by the lover she trusted.
Answer:D. being rejected by the lover