Coin Tossing. A balanced dime is tossed three times. The possible outcomes can be represented as follows.

HHH HTH THH TTH HHT HTT THT TTT Here, for example, HHT means that the first two tosses come up heads and the third tails. Find the probability that

a. exactly two of the three tosses come up heads.

b. the last two tosses come up tails.

c. all three tosses come up the same.

d. the second toss comes up heads.