Find the cost of fencing around a circular field of diameter 42 m at the rate of Rs.3 a meter?  Choose the correct choice from the following answers:	A) 138	B) 390	C) 393	D) 279	E) 222
2 * 22/7 * 21 = 131   131 * 3   = Rs.393   Answer: 393
<result>C</result>
Find the cost of fencing around a circular field of diameter 42 m at the rate of Rs.3 a meter?