The average permeability parallel to the bedding planes is given by________

• A. \(k = \frac{k_1 z_1+k_2 z_2+⋯.+k_n z_n}{z}*\frac{1}{2} \)
• B. \(k = \frac{1}{\frac{z_1}{k_1} +\frac{z_2}{k_2} +⋯+\frac{z_n}{k_n}} \)
• C. \(k = \frac{z}{\frac{z_1}{k_1} +\frac{z_2}{k_2} +⋯+\frac{z_n}{k_n}} \)
• D. \(k = \frac{k_1 z_1+k_2 z_2+⋯.+k_n z_n}{z} \)