When Demand Is Perfectly Inelastic,the Demand Curve Will Be

When demand is perfectly inelastic,the demand curve will be

A) negatively sloped, because buyers decrease their purchases when the price rises.
B) vertical, because buyers purchase the same amount as before whenever the price rises or falls.
C) positively sloped, because buyers respond by increasing the market quantity demanded of the good when price rises.
D) positively sloped, because buyers respond by increasing their total expenditure on the good when price rises.