Which of the following are sources of low-level radiation?
A) medical X-rays
B) nuclear waste truck passing by
C) burning of fossil fuels
D) all of the above
E) a and c only
D) all of the above
The sources of low-level radiation among the options provided are:
A) Medical X-rays
C) Burning of fossil fuels
Therefore, the correct option is E) a and c only.