The body of a proposal

explains the research process.
states a plan of action.
identifies the chosen solution.
examines the solution’s effectiveness.

I would say that the body of a proposal states a plan of action on how to proceed with a project to bring it to completion and explains the ability of the proposer to tackle the project in such a way as to complete it successfully.

Therefore the answer is:

States a plan of action

I hope that this has satisfied you.

The body of a proposal states a plan of action.  The main reason is because  it needs a beginning and, a middle and an end also known as the conclusion.

Hope this helps.

a. by accepting the election of president abraham lincoln in 1860 and convincing other southern states to do the same