In the following sentence, a part of the sentence is underlined. Below are given alternatives to the underlined part, which may improve the sentence. Choose the correct alternative. In case no improvement is needed, choose the option that indicates 'No improvement'.

Many successful criminal prosecutions rely largely or entirely on circumstantial evidence, and civil charges are frequently based on circumstantial or indirect evidence.

A. Frequently based at

B. Frequently based from

C. Frequently basis by

D. Frequent basis on