Relative masses of atoms and molecules — Chemistry 0620 IGCSE Question & Worked Solution

What does the term relative atomic mass, $A_r$, mean?

A$\left( \dfrac{\text{average mass of naturally occurring atoms of an element}}{\text{mass of one atom of } ^{12}\text{C}} \right) \times 12$
B$\dfrac{\text{average mass of naturally occurring atoms of an element}}{\text{mass of one atom of } ^{12}\text{C} \times 12}$
C$\dfrac{\text{average mass of naturally occurring atoms of an element}}{\text{mass of one atom of } ^{12}\text{C}}$
D$\dfrac{\text{mass of one atom of } ^{12}\text{C}}{\text{average mass of naturally occurring atoms of an element}}$

Relative masses of atoms and molecules — practice question