If a force 'F' is applied to stretch a wire of diameter 'd', of length 'L' and which is made of a material of Young's Modulus (Y) then the extension caused in it is equal to ___________.

• A. 4FY/(πLd2)
• B. 4FL/(πYd2)
• C. 2FL/(πYd2)
• D. 2FY/(πLd2)