If we draw a ball from an urn containing 10 numbered balls, with seven red balls that are numbered 1, 2, 3, 4, 5, 6, 7 and three that are green and are numbered 8, 9, 10, what is the probability of drawing a ball that is red and even?
a. 2/5
b. 3/10
c. 1/2
d. 4/7