The Amargosa Valley in Eastern California Desert Often Experiences a Cold

The Amargosa Valley in eastern California desert often experiences a cold evening wind that blows downvalley.Which of the following might explain this phenomenon?

A) Daytime heating causes a local low pressure that causes air to rush in by evening.
B) Moist Pacific air rising over the Sierra Nevada Mountains produces mountain precipitation,and as this air spills off the eastern escarpment,it forms the valley wind.
C) Night time cooling upvalley produces a cold,unstable air mass that is funneled down the valley to produce a valley wind.
D) It is a nighttime land breeze and there should be an accompanying daytime seabreeze up valley.