The central idea is the same as the main idea. Most of the time, the main idea is mentioned in the Title. Without reading the essay, I do not know what the central/main idea is.
D I,ll and lll I think that the answer
He told that Pawan would come that day
I believe the answer is A but i am not completely sure
An advantage would be that it would be first hand knowledge, so you could find out how normal people felt about situations.
A disadvantage would be that they are likely to be biased.
