atomic mass unit is calculated with reference to _____.\na carbon\nb oxygen\nc hydrogen\nd none of the above

atomic mass unit is calculated with reference to _____.\na carbon\nb oxygen\nc hydrogen\nd none of the above
Answer
Brief Explanations:
The atomic mass unit (amu) is defined as 1/12th of the mass of a carbon - 12 atom. So atomic mass unit is calculated with reference to carbon.
Answer:
a. Carbon