(1 point) determine whether the given set s is a subspace of the vector space v. a. v=c5(i), and s is the subset of v consisting of those functions satisfying the differential equation y(5)=0. b. v=p3, and s is the subset of p3 consisting of all polynomials of the form p(x)=ax3+bx. c. v=c3(i), and s is the subset of v consisting of those functions satisfying the differential equation y′′′−y′=1. d. v=mn(r), and s is the subset of all upper triangular matrices. e. v=r2, and s is the set of all vectors (x1,x2) in v satisfying 5x1+6x2=0. f. v=p2, and s is the subset of p2 consisting of all polynomials of the form p(x)=x2+c. g. v=r4, and s is the set of vectors of the form (0,x2,5,x4).