What is true regarding the cellular phone concept? a. a single radio broadcast tower system enables greater frequency reuse compared to a multiple cell phone system b. increasing base station transmit power is required to decrease the size of a cell c. by increasing the number and density of cells within a service area, you increase the overall complexity of the entire system d. decreasing the size of a cell expends greater power from the mobile device, and therefore reduces the device’s operating time

A mobile phone is a telecom device, which uses radio signals around an internet-connected area but is served at the same fixed location with a cell tower or transmitter, enabling calls to be transmitted electronically across a wide range, to a fixed over the Internet. By increasing the amount and size of layers within the same market area, the total size of the overall system is improved, and the wrong choices can be described as follows:

In option a, It is wrong because it can't reuse radio wave frequency.
In option b, It decreases the size of the cell, that's why it is incorrect.
In option d, It reduces the size of the cells, which increases the capacity of the smartphone and it also decreases the total time of the device, that's why it is wrong.