The relation between the air base (B), photographic base (b), flying height (H) and the focal length (f) of a vertical photograph, is

A. $${\text{B}} = \frac{{{\text{bH}}}}{{\text{f}}}$$

B. $${\text{B}} = \frac{{\text{f}}}{{{\text{bH}}}}$$

C. $${\text{B}} = \frac{{\text{b}}}{{{\text{fH}}}}$$

D. $${\text{B}} = \frac{{\text{H}}}{{{\text{bf}}}}$$

Answer: Option A