Please can you help me explain the answer to the below?

Suppose that the demand for lawn fertiliser can be expressed as: Qd = 5000-120p and that the supply of lawn fertiliser can be expressed as: Qs = 1000+80p where Q is measured in thousands of tons per year and P is measured in pounds per thousand tons. If demand increases 10%, by how much will price change?

A) Price will not increase B) Price increases by 7.50 C) Price increases by 1.23 D) Price increases by 10%