Option 1 -> Simple future tense - acceptable in conversational English for future completion.
Option 2 -> Simple present tense - doesn't match the future time reference "by the end of next April."
Option 3 -> Future perfect tense - grammatically precise for an action completed before a specific future time point.
Option 4 -> Grammatically incorrect construction - "will be" requires a present participle (graduating), not the base form.
Hence, Option 1 (will graduate) and Option 3 (will have graduated) -> When using "by" with a future time reference, the future perfect tense (will have graduated) is most grammatically accurate as it emphasizes completion before that deadline. However, the simple future (will graduate) is also widely accepted in everyday usage to express the same idea -> correct