Respuesta :
B is the only one. :)
Research shows that kindness is actually contagious, and those who witness acts of kindness are more likely to be kind.
B is correct.
Correct sentence: Research shows that kindness is actually contagious, and those who witness acts of kindness ARE more likely to be kind.
Incorrect sentence: research shows that kindness is actually contagious, and those who witness acts of kindness IS more likely to be kind.