The correct option is D 1+a2+b2+c2
Δ=∣∣
∣
∣∣a2+1abacabb2+1bcacbcc2+1∣∣
∣
∣∣
Multiplying C1,C2,C3 by a,b,c respectively
Δ=1abc∣∣
∣
∣∣a(a2+1)ab2ac2a2bb(b2+1)bc2a2cb2cc(c2+1)∣∣
∣
∣∣
Taking common a,b,c from R1,R2,R3 respectively
Δ=abcabc∣∣
∣
∣∣a2+1b2c2a2b2+1c2a2b2c2+1∣∣
∣
∣∣
Using the transformation, C1→C1+C2+C3
Δ=∣∣
∣
∣∣1+a2+b2+c2b2c21+a2+b2+c2b2+1c21+a2+b2+c2b2c2+1∣∣
∣
∣∣
=(1+a2+b2+c2)∣∣
∣
∣∣1b2c21b2+1c21b2c2+1∣∣
∣
∣∣
Applying R2→R2−R1 and R3→R3−R1
Δ=(1+a2+b2+c2)∣∣
∣∣1b2c2010001∣∣
∣∣
=(1+a2+b2+c2)