In a 2-stroke S.I. engine

A.exhaust and transfer (inlet) ports open and cloe simultaneously
B.exhaust port opens 5? before the transfer port and closes 5? after the transfer port
C.exhaust port opens 5? ahead of the transfer port but both ports close simultaneously
D.none of the above

In instrumentation, registering is

A.Production of continuous record on an instrument
B.Conversion of signal from one form to another
C.Indication by numbers or some other symbol of discrete increments, the value of some quantity
D.To perform various manipulations before indicating or recording results
E.None of the above