Adomestic initiative that president nixon was responsible for was the reduction of interest rates. the formal recognition of china. negotiating the salt i agreement. creating the environmental protection agency.

Correct  Creating the Environmental Protection Agency

Explanation/detail:

The formal recognition of China and Strategic Arms Limitations Talks (SALT) were foreign policy initiatives (not domestic).

As to interest rates, during the Nixon presidency, the Federal Reserve chairman, Arthur Burns, had begun raising interest rates.  In 1971, President Nixon exerted pressure on Burns and "the Fed" to keep interest rates down, but that only led to a decade of high inflation that caused other economic problems. So that was not a success for Nixon.

About the Environmental Protection Agency

President Nixon signed an executive order establishing the Environmental Protection Agency in 1970.  Subsequent committee hearings in the House of Representatives and the Senate ratified Nixon's order for the creation of the agency.  

Environmental issues had been gaining much attention during the 1960s, and the need for oversight became clear.  As Lily Rothman reported in a TIME magazine article:

- "Here's Why the Environmental Protection Agency Was Created," TIME, March 22, 2017

Nixon's administration felt it necessary to take action to address pollution problems in the American environment.

equal pay act of 1963. the equal pay act, signed in to law by president john f. kennedy on june 10, 1963, was one of the first federal anti-discrimination laws that addressed wage differences based on gender. they felt that this would prevent employers from undercutting future wages for men.

it was on the rise and doing very well and would continue to do well until the great depression from 1929-1939