The correct answer is: C. However
The word “however” is used to introduce a statement that contrasts with what has just been said. In this case, the sentence is saying that although Indian soldiers are generally honest, a few can be bribed. The word “however” helps to highlight this contrast.
The other options are not as appropriate in this context. The word “though” can also be used to introduce a contrast, but it is not as strong as “however.” The word “as” is used to introduce a comparison, and the word “if” is used to introduce a condition. Neither of these words would make sense in this sentence.
Here is a rewritten version of the sentence that uses the word “however”:
However honest Indian soldiers are, a few can be bribed.
This sentence is more concise and easier to understand. It also makes the contrast between the general honesty of Indian soldiers and the fact that a few can be bribed more explicit.