Cycling is a very useful way, especially in cities _______ bike paths have been built.

1. A.
   which
2. B.
   that
3. C.
   where
4. D.
   what

Cycling is a very useful way, especially in cities _______ bike paths have been built.

   A. which                 B. that              C. where                D. what

Cycling is a very useful way, especially in cities _______ bike paths have been built.

   A. which                        B. that                 C. where                    D. what

Cycling is a very useful way, especially in cities _______ bike paths have been built.