Select the most appropriate option to substitute the underlined segment in the given sentence. If there is no need to substitute it, Select No improvement.

The Kumbh Mela has been held at Allahabad, since centuries now because in the past two decades it has grown into a mega event.

A

for centuries now but in the past

B

N0 improvement

C

since centuries now but in the past

D

for centuries now moreover in the past