The given figures A, B, C and D are the examples of first true land vertebrates. They are dominant in mesozoic era and belong to phylum ‘X’. Identify ‘X’ and the animals which have four chambered heart. 

A. X – Reptile; B

B. X – Reptile; A

C. X – Amphibia, C

D. X – Pisces; D

Please do not use chat terms. Example: avoid using "grt" instead of "great".