Which Statement Is TRUE

Which statement is TRUE?

A) Elasticity of demand attempts to measure how fast quantity demanded increases when price increases.
B) If the elasticity of demand is -4, then economists know that the price is increasing at a faster rate than quantity demanded.
C) The price elasticity of demand is always a negative number, but economists generally ignore the negative sign.
D) The elasticity of demand is always the same as the elasticity of supply.