What is the right equation to find the vertical deflection in the pavement?

• A. \(Δ=\frac{3p}{2E(a^2+z^2 )^{1∕2}}\)
• B. \(Δ=\frac{3pa^2}{2E(a^2+z^2 )^{1∕2}}\)
• C. \(Δ=\frac{3pa^2}{2E(a^2+z^2 )^{3∕2}}\)
• D. \(Δ=\frac{3pa^2}{E(a^2+z^2 )^{1∕2}}\)