If a Geneticist Describes a Trait as Being 70% Penetrant

If a geneticist describes a trait as being 70% penetrant, what would they mean?

A) Individuals with the trait show variation in expression.
B) It is lethal in 30% of the individuals who have the trait.
C) Only 70% of the individuals who carry the allele(s) for a trait express the trait.
D) The trait is present in 70% of the population.