Answer:
The correct answer option is A. In concert halls.
Explanation:
Both Felix Mendellsohn and his sister Fanny Mendelssohn Hensel were the famous music composers in the era of 19th century.
Fanny Mendelssohn was a highly competent musician but her family thought that music was not a respectable career for a young woman. So Fanny made her debut as a soloist in Felix's piano concert at a benefit concert (in hall).
