The correct answer is (B) will begin.
"Will begin" is the correct future tense form. "Will began" is grammatically incorrect, while "should" and "can" express obligation/ability, not a scheduled future action.
In flight announcements, scheduled future events use simple future tense ("will + base verb"). "Will began" is wrong because "began" is past tense, not a base verb. "Should begin" implies obligation and "can begin" implies ability — neither fits a factual schedule announcement. Examiners expect students to identify the grammatically correct future tense form.