Does a woman pray Dhuhr at home as two rak'ahs or four rak'ahs?

The Dhuhr prayer consists of four rak'ahs by the consensus of Muslims, for both men and women, whether performed in the mosque or at home. The only exception is the traveler, who is permitted to shorten it to two rak'ahs. The Friday Dhuhr prayer, if performed at home, is four rak'ahs. However, if a woman prays it in the mosque with the congregation, her prayer is two rak'ahs, and this suffices for Dhuhr, even though it is not obligatory upon her.