In a Pure Metal the Collisions That Are Characterized by the Mean

Multiple Choice

In a pure metal the collisions that are characterized by the mean free time $\tau$ in the expression for the resistivity are chiefly between:

A) electrons and other electrons
B) electrons with energy about equal to the Fermi energy and atoms
C) all electrons and atoms
D) electrons with energy much less than the Fermi energy and atoms
E) atoms and other atoms