The total weight of the 21 students is:
\[ 21 \times 46 = 966 \, \text{kg}. \]
The total weight of the remaining 14 students is:
\[ 14 \times 41 = 574 \, \text{kg}. \]
The total weight of all students is:
\[ 966 + 574 = 1540 \, \text{kg}. \]
The total weight of all 35 students and the teacher is:
\[ 36 \times 44.75 = 1611 \, \text{kg}. \]
Thus, the weight of the teacher is:
\[ 1611 - 1540 = 71 \, \text{kg}. \]
So, the weight of the teacher is 71 kg, which corresponds to option (B).