Which one is a complex sentence?

উত্তর জানতে একটি অপশন বেছে নাও 👇

• কThough Rajib is ill, he regularly attends classses
• খDespite his illness, Rajib regularly attends classes
• গIn spite of his illness, Rajib regularly attends classes
• ঘRajib is ill, but regularly attends classes.