He had no idea of how the climb would be _______ he was half way up the mountain.

He had no idea of how the climb would be _______ he was half way up the mountain.

1. A.
   when
2. B.
   until
3. C.
   while
4. D.
   as

 He had no idea of how the climb would be _______ he was half way up the mountain.

A. when          B. until           C. while           D. as

He had no idea of how the climb would be _______ he was half way up the mountain.

 He had no idea of how the climb would be _______ he was half way up the mountain.

A. when           B. until         C. while           D. as