Step 1: Understanding the Concept
Dedifferentiation is the return of permanent cells to a dividing state. Redifferentiation is the loss of division and gain of specialisation.
Step 2: Check the Assertion
Cells made by the dedifferentiated meristem stop dividing and mature into xylem, phloem or cork, so (A) is true.
Step 3: Check the Reason
These products become permanent tissues and do not always remain meristematic, so (R) is false.
Final Answer:
(A) is true but (R) is false.
\[ \boxed{\text{(C) }\text{(A) is true but (R) is false.}} \]