Answer:
 A: 4×4
 B: 4×3
 C: 1×5
 D: 4×1
Explanation:
You are asked for the dimensions of the matrices shown. 
Matrix dimensions
The dimensions are expressed as ...
 (number of rows) × (number of columns)
The numbers of rows and columns are easily counted. The dimensions are seen to be ...
 A: 4×4
 B: 4×3
 C: 1×5
 D: 4×1