JEE Main Physics question

A stone is tied to one end of a string 50 cm long and is whirled in a horizontal circle with a constant speed. If the stone makes 10 revolutions in 20 s, what is the magnitude of the acceleration of the stone?

• (A)720 cm/s²
• (B)493 cm/s²Correct
• (C)860 cm/s²
• (D)990 cm/s²