A root CA certificate distinguishes itself from other certificates because:

A.
The root CA certificate has a special bit set in the Key Usage field.

B.
The root CA certificate has its serial number in a dedicated range.

C.
The root CA certificate issuer and subject are the same.

D.
The root CA certificate has a Subject Type equal to CA in its Basic Constraints.

E.
The root CA certificate has a Thumbprint.