jcherry99

The threshhold for gamma rays is between 1 * 10^17 Hz and 9*10^17 Hz

Since this question goes much beyond that the answer is you much be working with a gamma ray. It is "Best" classified this way because nothing else will fit. The others are all much lower.

nerdsrule2003

Answer:

a: gamma ray

Explanation:

on the electromagnetic spectrum, 10^21 is under the gamma ray section.