The answer is A i think if it’s wrong someone correct me
The answer is 2 more oxygen is needed
He is the only one that includes only mollecules
1 mol --------- 6.02x10²³ atoms
6.3 moles ---- ??
atoms = 6.3 * 6.02x10²³
= 3.7926x10²⁴ atoms
hope this helps!