Use the Sample Space Defined by the Experiment of Tossing

Multiple Choice

Use the sample space defined by the experiment of tossing a fair coin four times. Express the event that there are exactly two tails as a subset of the sample space.

A) {HHHH}
B) {TTTT, TTTH, TTHT, THTT, HTTT}
C) {HHTT, HTHT, THHT, HTTH, THTH, TTHH}
D) {TTTT}
E) {HHHH, HHHT, HHTH, HTHH, THHH}