Righteous Ron contracts to sell an eight$-$shot pump shotgun to Mad Mike. Later, Ron hears a rumor that Mike plans to use the shotgun in a shooting spree, Nonetheless, Ron sells Mike the gun. "A promise is a promise," says Ron. Which general style of ethical thinking is best exemplified by Ron's action and his remark?

a$.$ Deontology

b$.$ Consequentialism

c$.$ Cosmology

d$.$ Teleology