Pick up the correct statement from the following:
(A) The lines of sight while observing back sight and fore sight lie in the same horizontal plane
(B) The staff readings are measurements made vertically downwards from a horizontal plane
(C) The horizontal plane with reference to which staff readings are taken, coincides with the
level surface through the telescope axis
(D) All the above
(A) The lines of sight while observing back sight and fore sight lie in the same horizontal plane
(B) The staff readings are measurements made vertically downwards from a horizontal plane
(C) The horizontal plane with reference to which staff readings are taken, coincides with the
level surface through the telescope axis
(D) All the above