Which of the following sentences illustrates correct verb and verb tense usage?

Which of the following sentences illustrates correct verb and verb tense usage?

Possible several answers.

A. Until the snow is melting, the train is not able to move.
B. Until the snow does not melt, the train will not be able to move.
C. Until the snow melts, the train will not be able to move.
D. Until the snow will melt, the train will not be able to move.

Answer - C