Which of the following statements concerning the prospectus required by the Securities Act of 1933 is correct?

a. The prospectus is a part of the registration statement.

b. The prospectus should enable the SEC to pass on the merits of the securities.

c. The prospectus must be filed after an offer to sell.

d. The prospectus is prohibited from being distributed to the public until the SEC approves the accuracy of the facts embodied therein.