Assertion (A) Elementary phosphorus exists in three principal allotropic forms, i.e. white (or yellow), red (or violet) and black. Reason (R) Of the three forms, white phosphorus is the most important and most reactive.

• A. If both Assertion and Reason are true and Reason is correct explanation of Assertion
• B. If both Assertion and Reason are true but Reason is not the correct explanation of Assertion.
• C. If Assertion is true but Reason is false
• D. If both Assertion and Reason and false.