It is known that atom contains protons, neurons and electrons. If the mass of the neutron is assumed to half of its original value whereas that of the proton is assumed to be twice of its original value then the atomic mass of ${}_6^{14}C$ will be:

The correct option is C $14.28$ more

Number of protons=6, the mass of protons= 6 atm amu

Number of neutrons=8, the mass of neutrons= 8 amu

mass of ${}_6^{14}C$ =$6+8$=$14amu$

When the mass of neutrons is halved and the mass of protons is doubled, the mass of ${}_6^{14}C$ becomes

$\frac{8}{2}+6\times 2=16amu$

Percentage by which the mass has increased=$\frac{(16-14)}{14\times 100}=14.28$

Hence, mass of ${}_6^{14}C$ is=$14.28$ more

So, the correct option is $C$