Answer: The correct answer is Option d.
Step-by-step explanation:
Atomic number is defined as the number of protons or electrons that are present in a neutral atom.
Atomic number = number of protons = number of electrons
Atomic mass is defined as the sum of number of protons and neutrons that are present in an atom.
Atomic mass = Number of protons + Number of neutrons
General representation of an isotope is

where,
A = atomic mass
Z = atomic number
X = symbol of an atom
We are given:
Number of protons = atomic number = 6
Number of neutrons = 8
Atomic mass = 6 + 8 = 14
The atomic symbol is

Hence, the correct answer is Option d.