Lysander stop loving Hermia and begin loving Helena because, the magical flower juice was accidentally put in his eyes, making him fall in love with the first person he saw.
Answer: Option A
Step-by-step explanation:
Robin looking at Hermia and Lysander sleeping apart confuses Lysander with Demetrius. Since he has not seen both of them, he puts magical flower potion in the eyes of Lysander.
So, when we wake up, he sees Helena first. Due to the magical love potion, he falls in love with Helena. He stops loving Hermia. He gives an explanation that nature tells him about his love with Helena, and his relationship is over with Hermia.