Which of the following best describes the 'law of demand'?

Which of the following best describes the 'law of demand'?

(A) When price increases, the quantity demanded decreases.
(B) Demand decreases for a normal good when income increases.
(C) Legal authorities regulate prices.
(D) Sellers set the price that demanders pay.

Option (A) "When price increases, the quantity demanded decreases" is best describes the 'law of demand'.