Refer to figure. 
Regarding Air Data Computers, EASA learning objective 022.02.08.01.02 states: 'List the following possible input data: TAT; static pressure; total pressure; measured temperature; AoA; flaps position; landing gear position; stored aircraft data.' 
EASA learning objective 022.02.08.01.03 states: 'List the following possible output data, as applicable to aeroplanes or helicopters: IAS; TAS; SAT; TAT; Mach number; AoA; altitude; vertical speed; VMO/MMO pointer.'

The air data computer (ADC) acts as a central processing point for all the aircraft instruments and systems that need air data parameters in a digital format. Total pressure, static pressure, total air temperature (TAT) and angle of attack are input from their respective probes and the ADC performs the necessary calculations to output such parameters as true airspeed (TAS), altitude and calibrated airspeed (CAS)in a digital format that can be processed by the aircrafts systems that require it.

To calculate TAS the ADC needs to know the static air temperature (SAT). SAT is the temperature of the undisturbed air around an aircraft unaffected by the movement of the aircraft though it. Therefore SAT cannot be measured by a temperature probe attached to an aircraft in flight because as the air slows down, when impacting the probe, energy is released which causes an increase in temperature. This temperature increase is called the 'Ram Rise'.

Total Air Temperature (TAT) is the product of SAT plus the Ram Rise and this is what's measured by the TAT probe. TAT will always be higher than SAT.

To calculate TAS the ADC must derive SAT from the TAT input as part of its calculation. Therefore it is correct to say that the ADC uses its TAT input to calculate TAS.

Note: You may encounter similar questions where TAT isn't an answer option, in that situation case you must select SAT