B.  2744 cm³
Step-by-step explanation:
The area of the triangular base is ...
 A = 1/2bh
 A = 1/2(8 cm)(14 cm) = 56 cm²
The volume of the prism is ...
 V = Bh . . . . where B is the area of the triangular base.
 V = (56 cm²)(49 cm) = 2744 cm³