A Correct Formula (Dropping All Minus Signs)for the Calculation of the Elasticity

Multiple Choice

A correct formula (dropping all minus signs) for the calculation of the elasticity of demand between point Q₁,P₁ and point Q₂,P₂ is

A) [(P₂ - P₁) /(P₂ + P₁) ]/[(Q₂ - Q₁) /(Q₂ + Q₁) ].
B) [(P₂ - P₁) /P₁]/[(Q₂ - Q₁) /Q₁].
C) [(Q₂ - Q₁) /(Q₂ + Q₁) ]/[(P₂ -P₁) /(P₂ + P₁) ].
D) [(Q₂ -Q₁) /Q₂) ]/[(P₂ - P₁) /P₂].