Fill in the blank with the correct option:

You ____ buy your tickets before starting your journey. (Necessity)

Correct option is D

Explanation:

The correct answer is must.
The modal verb "must" is used to express strong necessity, obligation, or requirement. In this sentence, the speaker is emphasizing that buying tickets is necessary before starting the journey.

Examples of "Must" for Necessity:
You must wear a seatbelt while driving.
Students must submit their assignments on time.
You must carry your passport for international travel.

Information Booster:

Use of "Must" for Necessity:

Expresses rules, regulations, or strong necessity.

Used for formal or official instructions.

Implies urgency and importance.

Difference Between "Must" and Other Modals:

Must → Strong necessity ("You must buy a ticket.").
Should/Ought to → Moral duty ("You should buy a ticket.").
Can → Ability/Possibility ("You can buy a ticket if you want.").
May → Permission ("You may buy a ticket.").

Common Uses of "Must":
Rules & Regulations → "You must not smoke here."
Strong Advice → "You must visit this museum!"
Logical Deduction → "She must be the new teacher."