The mass of an atom of ¹²C is exactly 12 atomic mass units. Which of the following describes a mole of ¹²C atoms?

A) a sample that weighs exactly 12 atomic mass units
B) a sample that contains 6.02 × 10²³ atoms of ¹²C
C) a sample that weighs exactly 12 atomic mass units and a sample that contains 6.02 x 10²³ atoms of ¹²C
D) neither a sample that weighs exactly 12 atomic mass units or a sample that contains 6.02 x 10²³ atoms of ¹²C