A solid cylinder of diameter $100 \mathrm{~mm}$ and height $50 \mathrm{~mm}$ is forged between two frictionless flat dies to a height of $25 \mathrm{~mm}$. The percentage change in diameter is

(A) 0

(B) 2.07

(C) 20.7

(D) 41.4

A solid cylinder of diameter $100 \mathrm{~mm}$ and height $50 \mathrm{~mm}$ is forged between two frictionless flat dies to a height of $25 \mathrm{~mm}$. The percentage change in diameter is

(A) 0

(B) 2.07

(C) 20.7

(D) 41.4

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