What is the velocity potential for a slender body in uniform flow with perturbations?

• A. Φ(x, y, z) = V∞ x + ϕ(x, y, z)
• B. Φ(x, y, z) = V∞ z + ϕ(x, y, z)
• C. Φ(x, y, z) = V∞ y + ϕ(x, y, z)
• D. ∇Φ = u‘i + v‘j + (V∞ + w‘)k