In Humans, One Reason Why Mitochondrial Inheritance Is Strikingly Different

In humans, one reason why mitochondrial inheritance is strikingly different from nuclear inheritance is that:

A) mitochondrial DNA is single-stranded.
B) mitochondrial DNA is circular.
C) unlike nuclear inheritance, both parents do not contribute mitochondrial DNA.
D) unlike mitochondrial inheritance, only one parent contributes nuclear DNA.
E) mitochondrial inheritance is sex-linked.