It was then he (i) (hear) the jostle and squeal of elephants. Below him on each side of (ii) shallow river-bed, the elephants traveled. He could see the cows and babies and one
great old tusker. He (iii)(play) his trunk to and fro to learn whatever the breeze could tell
him, (iv)___ suddenly he hesitated.

Fill in the blank (iii) with appropriate tense?
a) play
b) was playing
c) was played
d) playing