Question

Menstrual cycle is generally of

• A. $21$ days
• B. $28$ days
• C. $30$ days
• D. $40$ days

Answer 1

The correct option is B $28$ days

• The reproductive cycle in female primates is known as menstrual cycle.
  
• In human females, menstruation is repeated at an average interval of about 28 days. The cycle of events starting from one menstruation until the next one is called the menstrual cycle.
  
• One ovum is released (ovulation) during the middle of the cycle.
  
• So, the correct option is '28 days'.