In an adiabatic compression, a gas's temperature (a) increases; (b) decreases; (c) remains the same; (d) cannot be determined from the information given.
Writing down the first law we get:
Because this is an adiabatic process, . Because the gas is compressed, the work is done on it, . Putting all this together we get:
Because the internal energy of an ideal gas is only a function of temperature, the temperature of the gas will increase.