Research Has Shown That Sex Has Positive Associations with Health

Research has shown that sex has positive associations with health and well-being.These associations can be best observed in which of the following?

A) The more physical intimacy partners reported engaging in together on a given day,the lower their experience of physical symptoms,such as headaches and insomnia.
B) Men and women burn 2/3 the amount of calories during sex as they would doing 30 minutes of exercise on a treadmill.
C) Cohabiting couples who were directed to kiss their partners more often reported decreased blood pressure,compared to those who did not increase their kissing.
D) Engaging in frequent intercourse reduces one's immune system,making them less susceptible to infection.