The Latin phrase economists use that means all else equal is

A) ceteris paribus.
B) cogito ergo sum.
C) carpe diem.
D) caveat emptor.

Cogito Ergo Sum

A philosophical statement by René Descartes, which translates to "I think, therefore I am," used to demonstrate the existence of the self and consciousness.

Carpe Diem

A Latin aphorism usually translated as "seize the day," encouraging individuals to make the most of the present moment without concern for the future.