John tossed a fair coin 4 times. What is the probability that the coin landed heads up exactly twice?	Choose the correct choice from the following choices
A) 0.15	B) 0.25	C) 0.3	D) 0.35	E) 0.4
The probability is exactly same as the cion landed tail up once. That is 4*(1/2)^4 = 4/16 =0.25.   The answer is, therefore, (0.25).
<result>B</result>
John tossed a fair coin 4 times. What is the probability that the coin landed heads up exactly twice?