Which of the following is not true about X-rays and gamma rays? i Both X-rays and gamma rays can destroy living cells of the body, ii. Gamma rays have the greatest frequency thus carry the highest amount of energy and considered to be more dangerous than X-rays. iii. Both gamma rays and X-rays can be used to kill cancer cells. iv. Both gamma rays and X-rays travel at the same speed,

a. i, ii, iii only
b. iii, iv only
c. iii only
d. iv only​