Please help solve the following questions

Consider the following vectors. Which of the following is true for s=axb? A s-a1b1 + a2b2 + a3b3 B s= (a1 + a2 + a3)*(b1 + b2 + b3) Cs=[a1*(b1 + b2 + b3); a2*(b1 + b2 + b3); a3*(b1 + b2 + b3)] D None of the above SUBMIT Multiple Choice Which one of the following statements is correct regarding partial pivoting in Gaussian elimination? If a zero- valued pivot is encountered... A Swap the pivot row with the row directly below it B Swap the pivot with a non-zero value in the same column C Swap the pivot with a non-zero value in the same row D None of the above