Suppose a circular queue of capacity $(n - 1)$ elements is implemented with an array of $n$ elements. Assume that the insertion and deletion operations are carried out using REAR and FRONT as array index variables, respectively. Initially, $\text{REAR} = \text{FRONT} = 0$. The conditions to detect queue full and queue empty are

In a circular queue of size $n$ designed to store up to $(n - 1)$ elements:

1. Queue Empty Condition: Initially, both FRONT and REAR point to the same index (0). The queue is empty whenever REAR == FRONT.

2. Queue Full Condition: To prevent the full condition from being indistinguishable from the empty condition, one position is kept empty. An element is inserted at (REAR + 1) mod n. Therefore, the queue is considered full when the next insertion position coincides with FRONT:

   $$(\text{REAR} + 1) \bmod n == \text{FRONT}$$

Hence, the correct choice is (A).