Improve the sentence by selecting the appropriate tense of the highlighted word.
He participated in several international conferences by the end of this year.

Correct option is B

The correct substitution of the highlighted words is (b) will have participated.
Explanation: The time marker “by the end of this year” refers to a specific point in the future. To express an action completed before that future point, English uses the Future Perfect tense: will have + past participle. Hence, will have participated correctly shows completion before the stated future deadline. (हिंदी: “इस वर्ष के अंत तक” भविष्य का संकेत देता है; अतः Future Perfect का प्रयोग होगा—will have + V3.)
Grammatical rule used: Future Perfect = will/shall + have + V3, used with future time-limit expressions like by next week/ by 2026/ by the end of this month.
Example: By the time the journal issue is released, she will have submitted her manuscript.
Information booster: Common triggers for Future Perfect include by, by the time, before, by the end of… when the reference point is in the future.
Why the other options are incorrect:
· (a) has participated — Present Perfect suits “so far/till now,” not a future deadline (हिंदी: “अब तक” का भाव, भविष्य नहीं).
· (c) had participated — Past Perfect needs a past reference point (by the end of last year), not a future one.
· (d) participates — Simple Present gives habitual sense; does not indicate completion before a future point.