A solid sphere of radius, r, and made of material with density ρs, is moving through the atmosphere (constant pressure, p) with a velocity, v. The net force ONLY due to atmospheric pressure (Fp) acting on the sphere at any time, t, is

• A. \(\frac{4}{3}\pi {r^3}{\rho _s}\frac{{dv}}{{dt}}\)
• B. zero
• C. πr2p
• D. 4π2p