A horse is tethered to one corner of a rectangular grassy field 46 m by 20 m with a rope 17 m long. Over how much area of the field can it graze?
Choose one:	A) 154 cm 2	B) 308 m 2	C) 227 m 2	D) 407 m 2	E) none of these

Rationale: "area of the shaded portion = 1 ⁄ 4 × π × ( 17 ) 2 = 227 m 2 answer c"
Answer: C