What change in transmitter power results in a 6 dB increase?

Because decibels are a logarithmic measurement, adding decibel values is equivalent to multiplying the corresponding power ratios. A basic rule to remember is that a 3 dB increase doubles the power. A 6 dB increase can be broken down into two consecutive 3 dB increases (3 dB + 3 dB). To find the total power change, you apply the factor of 2 twice: first you double the power, and then you double that new amount. Doubling the power twice (2 x 2) means multiplying the original power by 4. Multiplying by 2 would only be a 3 dB increase, and the other options do not match the correct logarithmic scaling.