A Piano Wire Has a Radius of 0

Multiple Choice

A piano wire has a radius of 0.50 mm. One end is fixed and the other is wrapped around a tuning peg, which has a diameter of 3.5 mm and is 80 cm away. After the wire just becomes taut, the peg is given three full turns. What is the tension in the wire? Young's modulus for steel is
20 × 10¹⁰ N/m².

A) 3.8 kN
B) 4.3 kN
C) 6.5 kN
D) 8.7 kN
E) 9.8 kN