Answer:
10^8 waves per second
Step-by-step explanation:
Cell phones operate by transmission of a particular type of electromagnetic waves called Radio waves.
Radio waves operate in the frequency range of 3kHz to 300GHz (i.e. 3 * 10³ to 3 * 10¹¹ waves per second).
Hence, the only possible option for frequency of a cell phone tower is 10^8 waves per second.