When Santa arrived in Texas on Christmas eve, it was cold and snowy and the roofs were very icy. Santa landed his sleigh and stepped out onto the icy roof. As Santa's foot pushed backward, an equal
and opposite force pushed the sleigh forward on the icy surface. Luckily, Rudolph and Dancer kept
the sleigh from sliding off the roof!

Is this the Law of Inertia (1st), Law of Acceleration (2nd) or Law of Action/Reaction (3rd)?

Explain
your reasoning.