One mole of any substance contains:
A$6.022\times 10^{23}$ entities, by Avogadro's number
B$1$ entity only, regardless of substance
C$12$ entities, the same as carbon's atomic mass
D$10^{6}$ entities, the macroscopic count of particles
Answer & Solution
Correct answer: A. $6.022\times 10^{23}$ entities, by Avogadro's number
Avogadro's number $N_A = 6.022\times 10^{23}$ per mole.