In the passage on voting behaviour, select the correct verb form to complete the sentence: "But recent research across India _________ that those who spend the most do not always win elections."

Introduction / Context:
This question also belongs to the same passage on voting and focuses on tense and subject verb agreement. The sentence is But recent research across India _________ that those who spend the most do not always win elections. You must choose the verb form that correctly matches the subject research and expresses a finding that is relevant up to the present.

Given Data / Assumptions:

• Subject: recent research across India.
• The subject research is singular, even though across India is a phrase of place.
• The sentence describes findings that are still valid.
• Options: show, has shown, had shown, showed, shows.

Concept / Approach:
Research, when used as a noun in English, is uncountable and takes a singular verb. To talk about studies done recently whose conclusions still hold, English commonly uses the present perfect tense, has shown. This tense links past research activities to their continuing relevance. Therefore the correct form should combine singular agreement and present perfect, giving has shown. Other choices either break the agreement or change the time reference.

Step-by-Step Solution:
Step 1: Identify the grammatical subject: recent research across India, which is singular.Step 2: Decide on the tense. The word recent indicates that the studies were conducted in the near past and their results still matter now.Step 3: Present perfect is appropriate for such findings, so we look for has plus past participle.Step 4: Combine singular subject with present perfect to get has shown.Step 5: Confirm that the full sentence reads smoothly: recent research across India has shown that those who spend the most do not always win elections.

Verification / Alternative check:
Read the sentence with each option. Research across India show is ungrammatical because show is plural. Had shown and showed push the whole statement into a completed past with less emphasis on current relevance. Shows is simple present and does not highlight the recent research activity. Only has shown preserves both the timing and the continuing importance of the findings, which matches the context of the passage.

Why Other Options Are Wrong:

• show: This is plural and does not agree with the singular noun research.
• had shown: Past perfect is used when one past event happened before another past event, which is not the situation here.
• showed: Simple past is possible, but it does not emphasise that the findings are still valid and relevant.
• shows: Simple present does not directly convey the idea of recent studies producing these results.

Common Pitfalls:
Candidates often treat research as plural and wrongly combine it with show. Another mistake is to choose showed simply because it feels natural, but ignoring the hint given by recent. Always check whether the subject is grammatically singular or plural and whether the time context suggests simple past or present perfect.

Final Answer:
The correct verb form is has shown.