Correct option is C
Rise and Fall Method :
⇒ Rise and fall method is used for fly leveling, profile leveling.
⇒ Rise and fall method provides check on fore sight, back sight and intermediate sight.
⇒ ΣBS-ΣFS=ΣRise-ΣFall=Last RL-First RL
Height of Instrument Method (HI) :
⇒ It is also known as line of collimation method.
⇒ If number of intermediate sight is more than HI method is adopted.
⇒ It is used for small areas.
⇒ It does not provide check on intermediate sight.
⇒ Check : ΣBS-ΣFS= Last RL – First RL
