Concept:
The latch needle is the most widely used needle in weft knitting (circular and flat-bed). It consists of a hook, a stem, and a swinging latch pivoted on the stem.
Step 1: Analyzing Assertion (A).
Unlike bearded needles (which require a "presser") or compound needles (which require a separate sliding element), the latch needle closes its own hook during the knitting cycle. Thus, it is considered self-sufficient. Thus, (A) is correct.
Step 2: Analyzing Reason (R).
The "automatic" closure happens because the previously formed loop slides up and down the needle stem. As the needle rises, the loop hits the underside of the latch and opens it. As the needle descends, the loop slides over the latch, pushing it upward to close the hook. Thus, (R) is correct.
Step 3: Evaluating the Relationship.
The physical movement of the loop described in (R) is exactly why no extra mechanical element is needed to close the hook (A).