For each of the following sets with listed addition operation, is the set a vector space? Explain. If not, explain why and provide a counter example.
(A) The set of 4×6 matrices with matrix addition.
(B) The set of all 3rd degree polynomials with function addition.
(C) The set {(x,y)∈R 2∣x≥0} with vector addition.
(D) The set of all invertible 2×2 matrices with matrix addition.