It should be reported without ATC request that（ ）.
A.A change in cruising true airspeed of 10 knots or 5%, whichever is greater.
B.A change in cruising true airspeed of 10 knots or 10%, whichever is greater.
C.A change in cruising true airspeed of 5 knots or 10%, whichever is greater.
正确答案是A