I say, “Homemaker.” Never been declined.
Never go on any financial services shop or one where you portry yourself as ready to buy a big ticket items without a "back story". Occupation, general area where you live or work, what interests you in the account/products. Sales people are trained to ask those questions. Among other things it makes them seem to be interested in you as a person. It may also be a way of finding out if you are ready, willing and able to buy what they are selling. They are also trained not to waste their time on you if those 3 criteria are not met.
With it being a credit card opening shop, the OP has to give a truthful answer regarding employment.
"House cleaning", if the scenario doesn't require a large net worth. "Recently inherited a lot of money" if it does.