'There is smoke on the distant hill. Since smoke is always accompanied by fire, the hill must have fire too.' Which of the following corresponds to the middle term (hetu) in the above argument?

Given below are two statements: one is labeled as Assertion (A) and the other as Reason (R). Assertion (A): According to classical Indian logic (Nyaya), 'all knowable things are nameable.' The pot is a knowable thing. Therefore, the pot is nameable. This is an invalid inference. Reason (R): In the Kevalanvayi inference, the middle term and the major term agree only in presence; there is no negative instance where their agreement in absence can be verified. In light of the above statements, select the most appropriate answer from the options given below: