Read this passage. "Did you know that doing good deeds might help you feel better, not just emotionally, but physically? Here are a few ways that being kind benefits your mind and body. First, helping others increases serotonin in your brain. Serotonin is linked to feelings of satisfaction and wellbeing. Being kind to others also releases endorphins, which contributes to happiness. Reduced anxiety and stress is another effect of showing kindness to others. Research has shown that people who performed acts of kindness experienced positive moods, such as joy, interest, and alertness. Over time, these positive feelings counteract and reduce feelings of social anxiety. Performing acts of kindness also increased people's ability to cope with stress as well as decreased the effects of stress on their bodies.
Surprisingly, being kind is also linked to heart health. People who do acts of kindness experience a release of oxytocin, which dilates the blood vessels, lowering blood pressure. Additionally, loneliness, or social isolation, actually puts stress on the cardiovascular system. The stress of social isolation is as big of a risk to your heart as having high cholesterol, having high blood pressure, or smoking. The answer to loneliness is to have a strong network of friends and family to rely on. What better way to build relationships than by showing kindness?"
What is the implied main idea?

a. Performing acts of kindness increases the ability to cope with stress.

b. Being kind to your family and friends is more beneficial than being kind to strangers.

c. The simple act of being kind can improve your health.

d. Kindness is the best way to be stay physically fit and be consistently happy.