Step 1: Identify the time marker in the sentence. The word 'yesterday' clearly indicates that the action took place in the past.
Step 2: Determine the correct verb tense. A specific time marker in the past ('yesterday') requires the use of the Simple Past tense.
Step 3: Find the Simple Past form of the verb 'scold'. The past tense of the regular verb 'scold' is 'scolded'.
Step 4: Complete the sentence. The correct sentence is: "The teacher scolded the class yesterday."