The value of a call option can never exceed...(please explain)

a. zero.

b. the difference between the underlying stock price and the options exercise price.

c. the option's exercise price.

d. the underlying stock price.

Compared to a European option, the value of an otherwise identical American option is...(please explain)

a. sometimes less, and never greater.

b. always equal to the value of the European option.

c.sometimes greater, and never less.

d. always greater.

e. always less.

It is never rational to exercise an American ____ option on a ___________ stock prior to its expiration date.(please explain)

a. call ... dividend-paying

b. put ... non-dividend-paying

c. call ... non-dividend-paying

d. put ... dividend-paying