Linear algebra q-5 part-b

Let V R'(R) be vector space. Which of the following is subspace of V? | (a) {(a.b.c)E Vla 2b 2c) )(a,b,c)e V la* +b?+c*20} (b) {(a,b,c)E Vla+b2 c} d) {(a,b.c)E V la' +b? +c?21}|