Answer;
A. 0 ° C and B. 273 K
The temperature of a system in thermal equilibrium with another system made up of ice and water at 1 ATM of pressure is either 0 degrees Celsius or 273 Kelvin.
A substance's temperature increases as a direct result of kinetic energy being added to the particles of the substance.
Thermal equilibrium is when there is no net flow of thermal energy between them when they are connected by a path permeable to heat.