MC Mary Kom was declared the winner in the 48 kg category at the Asian Boxing Championship held in Ho Chi Minh City, Vietnam in November 2017.
Option 1 - 48 kg: This is the correct answer. Mary Kom won the gold medal in this weight category.
Option 2 - 51 kg: Mary Kom did not win the gold medal in this weight category. She won in the 48 kg category.
Option 3 - 54 kg: Mary Kom did not win the gold medal in this weight category. She won in the 48 kg category.
Option 4 - 57 kg: Mary Kom did not win the gold medal in this weight category. She won in the 48 kg category.
To summarize, Mary Kom`s victory came in the 48 kg weight category and not in any of the other weight categories mentioned.