If A1, B1, C1 … are the cofactors of the elements a1, b1, c1... of the matrix
⎡⎢⎣a1b1c1a2b2c2a3b3c3⎤⎥⎦ then ∣∣∣B2C2B3C3∣∣∣=
Here as per the statement of the question B2, C2, B3 and C3 are the co factors of b2,c2 b3 and c3 respectively. So let’s calculate them first.
Solving this we will get
Now if you look carefully, the underlined part is the value of the determinant D expanded along the first row
So, ∣∣∣B2C2B3C3∣∣∣=a1 D which is the option (a)