The correct answer is: A. Questionnaire.
A questionnaire is a list of questions that are asked to a group of people in order to gather information about a particular topic. Questionnaires are a common tool for research, as they are relatively easy to administer and can be used to collect data from a large number of people.
In the case of the researcher who wants to study the future of the Congress-I in India, a questionnaire would be a good tool to use because it would allow him to collect data from a large number of people. The questionnaire could be designed to ask questions about people’s opinions on the Congress-I, their expectations for the future of the party, and their reasons for supporting or not supporting the party.
The other options are not as appropriate for this study. A schedule is a list of tasks that need to be completed, and it would not be helpful for gathering information about people’s opinions on the Congress-I. An interview is a conversation between two people, and it would be more time-consuming and expensive to conduct interviews with a large number of people. A rating scale is a tool that is used to measure people’s opinions on a particular topic, but it would not be appropriate for this study because it would not allow the researcher to collect detailed information about people’s opinions on the Congress-I.