Which one of the following is not closed under the operation being performed

Remember that polynomials are closed under addition, subtraction, and multiplication, but they are not closed under division. The only division you have there is B; therefore the correct answer is B.

A. . The result is still a polynomial; therefore, answer A is incorrect.

B. with a remainder of 26. The result is not a polynomial anymore; therefore, B is the correct answer.

C. . The result is still a polynomial; therefore, answer C is incorrect.

D. . The result is still a polynomial; therefore, answer D is incorrect.

How many shares did he have to begin with?