You must work hard for success (Make it compound).
Work hard and you will succeed.
Correct
Work hard for success.
Word hard for the success.
Work hard to success.
Explanation:
Correct Answer is: Work hard and you will succeed.
Compound sentence এ and, or, else, either or, therefore প্রভৃতি conjunction দ্বারা দুটি independent clause কে যুক্ত করা হয়।