A Jet Aircraft,in Level Flight at Constant Speed,is Observed Directly

Multiple Choice

A jet aircraft,in level flight at constant speed,is observed directly overhead.A sonic boom is heard later,at which time the line of sight to the aircraft forms a 51° angle with respect to the horizontal.The speed of sound is .The altitude of the aircraft is closest to

A) 6700 m.
B) 5400 m.
C) 8300 m.
D) 2700 m.
E) 13,000 m.