Synchronized swimming demands some water skills, a...

Câu hỏi: Synchronized swimming demands some water skills, and requires incredible strength, endurance, flexibility, grace, artistry and precise timing, _______.

A. while upside down underwater with exceptional breath control

B. because of exceptional breath control while upside down underwater

C. also exceptional breath control is required while upside down underwater

D. as well as exceptional breath control while upside down underwater