Birds and reptiles are most closely related, Frogs are more closely related to birds than fish and fish are the most primitive are three statements that are correct because a cladogram is considering a diagram that is used in cladistics.
This type of diagram is there to show relations between organisms and in this case, it is true that birds and reptiles are related most closely, frogs are more closely related to birds and the fish( C is incorrect) is the most primitive( that is why answer A. is not correct).
