Fill in the blanks using the correct tense of the verbs given in brackets. Sam ______(daydream) when the teacher called him.

Was daydreaming (correct tense): In this context, the past continuous tense "was daydreaming" is appropriate as it indicates an ongoing action in the past when the teacher called him.   Options:   (a) Daydreaming: This is the present participle form, and it doesn't convey the correct past tense for the context. (b) Was daydreaming: This is the correct past continuous tense, indicating the ongoing action at the time the teacher called him. (c) Had daydream: This is not the appropriate tense for the context. The past perfect tense is not needed here. (d) Has been daydreaming: This is the present perfect continuous tense, and it is not suitable for indicating an action in the past at a specific moment.