A neutral stimulus can be made into a reinforcer by?

A neutral stimulus can indeed be transformed into a reinforcer through the process of pairing it with an unconditioned stimulus. This pairing allows the neutral stimulus to acquire the ability to elicit a response after being consistently associated with an unconditioned stimulus, which naturally elicits the desired response. For example, if a neutral stimulus like a bell is repeatedly paired with the presentation of food (the unconditioned stimulus), the bell can eventually elicit salivation on its own, thus becoming a conditioned reinforcer.

The other options do not effectively describe the process by which a neutral stimulus is converted into a reinforcer. Punishing a competing behavior focuses on discipline rather than reinforcement, presenting the neutral stimulus randomly does not establish a consistent association, and merging it with another reinforcer does not necessarily create the reinforcer status of the neutral stimulus itself. The effective mechanism is through the established association with an unconditioned stimulus, leading to a learned response.