The correct form of the verb in this sentence is "wanted," which is the past tense (V2) form of the verb "want." Here's a detailed explanation:

• V1 (base form): "want" - used for present tense, e.g., "I want to become an IAS officer."
• V2 (past tense): "wanted" - used for past tense, e.g., "He wanted to become an IAS officer."
• V3 (past participle): "wanted" - used for forming perfect tenses, e.g., "He has wanted to become an IAS officer."

In the given sentence, the action of wanting to become an IAS officer is described in the past tense, indicating a desire or intention in the past. Therefore, the correct form to use is "wanted," making option 1 the correct answer:

He wanted to become an IAS officer.