A sentence/a part of the sentence is underlined. Four alternatives are given to the underlined part which will improve the sentence. Choose the correct alternative and click the button corresponding to it. In case no improvement is needed, click the button corresponding to "No improvement".
Knowing that the area was prone to earthquakes, all the buildings were reinforced with additional concrete.

A

On being prone to earthquakes,

B

Having been knowing that the area was prone to earthquakes,

C

Since the area was known to be prone to earthquakes,

D

No improvement