The expected answers were:
(a)

(b) (i)      A transmission transformer (always step-up) receives electric power  from a nearby generating facility and uses a large power  transformer to increase the voltage for transmission to distant  locations.   
     (ii)      A distribution transformer steps down transmission or sub- transmission voltage to distribution voltage.
     (iii)     Isolator is used to open or close a circuit to enable maintenance or repair work to be done.
     (iv)     A fuse is used to protect circuit (transformer) and distribution line.
The question was on Electrical Energy Supply. It was unpopular with the  candidates. The candidates’ performance was reported to be poor.