Which of the following statements are correct about the early exercise of Amer

Which of the following statements are correct about the early exercise of American options?

i. It is never optimal to exercise an American call option on a non-dividend-paying stock before the expiration date.

ii. It can be optimal to exercise an American put option on a non-dividend-paying stock early.

iii. It can be optimal to exercise an American call option on a non-dividend-paying stock early.

iv. It is never optimal to exercise an American put option on a non-dividend-paying stock before the expiration date.

a. i and ii

b. i and iv

c. ii and iii

d. iii and iv