The Hedge Ratio
A)Is the Size of the Long (Short) $\frac { C _ { u T } - C _ { d T } } { S _ { 0 } ( u - d ) }$

The hedge ratio

A) Is the size of the long (short) position the investor must have in the underlying asset per option the investor must write (buy) to have a risk-free offsetting investment that will result in the investor perfectly hedging the option.
B) $\frac { C _ { u T } - C _ { d T } } { S _ { 0 } ( u - d ) }$
C) Is related to the number of options that an investor can write without unlimited loss while holding a certain amount of the underlying asset.
D) All of the above