Q. Fill in the blank from given options. By next July, I ________ in this office for ten years.

Explanation:

The clause “By next July” sets a future reference point, and “for ten years” indicates duration up to that point. To express an action that started in the past and will continue up to a specified future time, we use the Future Perfect Continuous tense: will have been + V-ing.
Correct: “By next July, I will have been working in this office for ten years.”

Why others are wrong:
– Option 1: will work — Simple future does not fit with “by” + future time expressing culmination; it lacks the perfect aspect needed for duration up to a future point.
– Option 3: worked — Simple past cannot be used with a future time marker (“by next July”).
– Option 4: will be worked — Passive voice is incorrect here; “work” in the sense of employment is intransitive and not passivized in this context.

Note: Future perfect simple (“will have worked”) could also be acceptable to emphasize completion, but it is not among the options.