Step 1: Identify the neither/nor construction. The sentence uses 'neither ... nor ...', which links two subjects: 'the teacher' (singular) and 'the pupils' (plural). Step 2: Apply the proximity rule. When a neither/nor or either/or construction joins subjects of different numbers, the verb agrees with the subject nearest to it. The nearer subject here is 'the pupils' (plural). Step 3: Determine the correct tense. The sentence is set in the past ('had already rung'), so a past-tense plural verb is needed. Step 4: Select the correct form. 'were' is the past-tense plural form of 'to be'. Answer: were