In the following passage, some of the words have been left out. Read the passage carefully and select the correct answer for the given blank out of the four alternatives.
But what does this enthusiasm for voting actually _________? One popular theory _________ that poor people _________ because they are intimidated into doing so. Intimidation occurs for sure but why then, voters in places where there is no intimidation do so? Another theory is that people vote in return for _________. But recent research across India _________ that those who spend the most do not always win elections and voters do not feel any obligation to vote for those handing out freebies. In fact, they often accept the goodies from all parties but vote for only one.

But recent research across India _________ that those who spend the most do not always win elections

1. A
   show
2. B
   has shown
3. C
   had shown
4. D
   showed