To determine the elevation of a point B from the elevation of a point A, which is 511.6 ft. When the transit was set up over the point A, the height of the transverse axis above that point was 4.92 ft. Also, when a leveling rod was held vertically on the point B and the reading of the horizontal cross line on the rod was made 3.00 ft, the vertical angle between the horizontal line CD through the transverse axis of the transit and the inclined line of sight was + 10°36'. After a point E was marked on the ground on the line between A and B and at a horizontal distance of 60.00 ft from A, the transit was set up over the point E. It was found that the difference in elevation between the point A and the transverse axis F of the transit at E was 7.24 ft. Also, when the reading of the horizontal cross line on a leveling rod held vertically on the point B was made 3.00 ft, the vertical angle between the horizontal line through F and the inclined line of sight was 20°48'. The elevation of the point B is

A. 540.9 ft. C. 536.4 ft.
B. 537.9 ft. B. 533.4 ft.