Which of the following is true ? Also please explain why each option is correct or not correct.

a)an american call option on foreign currency will never be exercised early.

b)for options on futures,the value of at the money call option must equal the value of the at the money put option.

c)for options on foreign currency,value of the at the money call option must equal the value of the at the money put option.

d)a european put may be worth more than an otherwise equivalent american put.

e) none of the above.