Which one is correct about the AP conduction velocity of nerve fiber

A、Increaseofthetemperaturewithinphysiologicallimitwillincreasetheconductionvelocity.;
B、Thefiberwithbigdiameteralwaysconductsfaster.;
C、TheincreaseofextracellularK+willincreasetheconductionvelocity;
D、Myelinationofnervefiberalwaysdecreasestheconductionvelocity.;
E、Anesthesiadonotinfluencetheconductionvelocity.