Match the following in the context of Indian mining practice:

Equipment	Power source
a. Rocker shovel	1. Battery
b. Locomotive	2. Compressed air
c. Shearer	3. Electricity (Maximum voltage 6.6 kV AC)
d. Dragline (24 m3 bucket capacity)	4. Electricity (Maximum voltage 1.1 kV AC)

A. a-1, b-2, c-3, d-4

B. a-2, b-1, c-4, d-3

C. a-2, b-1, c-3, d-4

D. a-1, b-3, c-2, d-4

Answer: Option B