Determine the correctness or otherwise of the following Assertion[ a] and Reason [r] Assertion: An antigen recognized by one immunoglobulin subtype is not recognized by any other subtype. Reason: Immunoglobulin subtypes differ from each other body in the variable and in the constant regions.

• A. Both [a] and [r] are true and [r] is the correct reason for [a]
• B. Both [a] and [r] are true but [r] is not the correct reason for [a]
• C. Both [a] and [r] are false
• D. [a] is true but [r] is false