题目

The young boy saw me, or rather, he saw the car and quickly ran up to me, eager to sell his bunches (串) of bananas and bags of peanuts. Though he appeared to be about twelve, he seemed to have already known the bitterness of life. Banana 300 naira. Peanuts 200 naira     He said in a low voice. I bargained him down to 200 total for the fruit and nuts. When he agreed, I handed him a 500 naira bill He didn't have change, so I told him not to worry.     He said thanks and smiled a row of perfect teeth.      When, two weeks later, I saw the boy again, I was more aware of my posit已知圆（x-a）2+（y-b）2=r2的圆心为抛物线y2=4x的焦点，且与直线3x+4y+2=0相切，则该圆的方程为 [     ]A.              B.C.                D.