Is it permissible for a woman to answer a knock at the door from behind it if she is alone in the house, and what is the evidence for that?

A woman is permitted to answer someone who knocks on the door from behind the door, provided she does not speak in a soft, alluring manner, in accordance with the Almighty’s saying: ﴿So do not speak in a soft, alluring manner, lest he in whose heart is a disease should be moved with desire; but speak in a customary manner﴾ [Al-Ahzab: 32]. Evidence for this permissibility is also found in the Almighty's saying: ﴿And when you ask them (his wives) for anything, ask them from behind a screen﴾ [Al-Ahzab: 53], and a question requires an answer devoid of a soft, alluring tone.