The equal credit opportunity act of 1974 prohibited banks from denying someone credit based on

gender
income
education
debt

"gender"

Explanation:

The Equal Credit Opportunity Act, ECOA, created in 1974, prohibits discrimination against consumers by sex, nationality, marital status, age, color, race, for receiving public assistance or religion.

Whoever has applied for a mortgage loan knows that most of these details are asked in the process. What is illegal and forbidden to ask is your religion. But, no mortgage institution can use this information to decide, approve or deny your application, or to establish the terms and conditions of the loan. For example, no loan originator or mortgage bank can impose different loan terms and conditions on the rest of consumers based on their race, marital status or sex.

d is the best answer for this question.