A small source of sound vibrating at frequenc 500 Hz is rotated in a circle of radius `(100//pi) ` cm at a constant angular speed of 5.0 revolutions per second . The speed of sound in air is 330 m . ` s^(-1)` . An observer (A) is situated at a great distance on a straight line perpendicular to the plane of the circle , through its centre . Another observer (B) is at rest at a great distance from the centre of the circle byt nearly in the same plane . After something the source of sound comes to rest after reaching the centre of the circle . At that time , another observer (C) moves towards the source with a constant speed of 20 m . ` s^(-1)` , along the radial line to the centre
The mininum and the maximum values of the apparent frequency heard by B will be

Options

A. 455 Hz and 535 Hz
B. 485 Hz and 515 Hz
C. 485 Hz and 500 Hz
D. 500 Hz and 515 hz

Answer

b.c.d