Proposals are seller prepared documents that describe the seller's ability to provide requested services? See below for remaining portion

Definitely choices A, C & D are out.

Choice "B" is vague.

"Request seller responses" may refer to the responses from the following procurement documents:

1) Request for Information (RFI)

2) Request for Quotation (RFQ), Invitation to Bid (ITB), or Request for Proposal (RFP)

For number 1, RFI, this document is not a request for offers. This document is submitted to suppliers/service providers if the requesting unit/organization/company has no idea about their "requirement" and would like to know information about it to assist them in creating the specifications of their requirement. Also this may refer to the inquiry from the requestng party to know about the goods and/or services being offered by the suppliers/service providers - which is actually part of the process of selection of suppliers/services providers to be invited.

For number 2, RFQ, ITB, and RFP refers to tender documents or soilicitation dcouments. These documents are the ones used to solicit offers.

So if choice "B" refers to the solicitation documents itemized in "no. 2" above then "choice B" is my answer to your question.

If not, there is no correct answer in the given choices.

It is "B".

To eleicit the proposal is to get speicifed feedback from the supplier.

process B is quite similar to rfq 

Proposals can be eiter a direct consequence of an rfq / rfp issued by purchasing organization requesting a proposal from vendor or an open offer sent in hope of being taken into consideration in any upcoming tender.

So neither answer is necessarily absolutely correct.

Elicit the proposalrequirements that affect effectiveness, efficiency and satisfaction of a user achieving his/her goals in a defined context of use. And option 'A' select seller the process is used to elicite the proposal.

Select Sellers is the process for reviewing offers, choosing among potential sellers, and negotiating written contract with each seller and this process  receives bids or proposals and applies evaluation criteria, as applicable, to select one or more sellers who are both qualified and acceptable as a seller.

The proposal comes after the customer has selected the vendor and made the order. and waits for the seller prepares a quote, once the client receives the quote can confirm.

so it B the nearest response

A. Select sellers                             .      

a  seller must supply document showing his ability to provide quality service and selling his proposal to be perfect match for the project.

The most appropriate option is

B. Request seller responses