Answer: The answer is (B).
Step-by-step explanation: We are given four options and we are to select which matrix can be multiplied to the left of a vector matrix to get a new vector matrix. The order of a vector matrix is either n × 1 or 1 × n.
For (A): The order of the matrix is 2 × 1. If we multiply this matrix by a vector matrix of order 1 × 2, then the resulting matrix will be of order 2 × 2, which is not a vector matrix.
For (B): The order of the matrix is 3 × 2. If we multiply this matrix by a vector matrix of order 2 × 1, then the resulting matrix will be of order 3 × 1, which is a new vector matrix.
For (C): The order of the matrix is 2 × 2. If we multiply this matrix by a vector matrix of order 2 × 1, then the resulting matrix will be of order 2 × 1, which is a vector matrix of order same as before.
For (D): The order of the matrix is 1 × 2. If we multiply this matrix by a vector matrix of order 2 × 1, then the resulting matrix will be of order 1 × 1, which is a not vector matrix.
Thus, the correct option is (B).
