Choose the right option. My dear granny ___ a pensioner by 2025.

The correct option is "will have become". Explanation: We need to use the Future Perfect tense. This tense is used to describe an action that will be completed before a specific time in the future. In this case, the specific time in the future is "by 2025". The action of becoming a pensioner will be completed before 2025. So, the correct sentence is: My dear granny will have become a pensioner by 2025. Answer: will have become