The correct answer is - ক) Though he was lazy, he passed the exam.

- Simple sentence-এ যদি In spite of ব্যবহৃত হয়, তাহলে Complex sentence করতে হলে Though/Although ব্যবহার করতে হয়।
- আবার, Complex sentence-এ Though/Although থাকলে, সেটিকে Simple sentence করতে হলে In spite of বসে।

• Example:
Simple: In spite of his poverty, he is happy.
Complex: Though he is poor, he is happy.

• More examples:
Simple: In spite of the bad weather, we went there.
Complex: Though the weather was bad, we went there.

Simple: In spite of his bad behaviour, people mix with him.
Complex: Though his behaviour is bad, people mix with him.

Simple: In spite of his honesty, he is not happy.
Complex:Though he is honest, he is not happy.
or, Honest as he is, he is not happy.

Simple: In spite of his cruelty, I love him.
Complex: Though he is cruel, I love him.

• Other options:
খ) Though he is lazy, he fails the exam.
অর্থ পুরোপুরি আলাদা, কারণ ফলাফল ভিন্ন (pass vs fail)।
"he fails the exam" - মূল বাক্যের বিপরীত অর্থ।
তাই সঠিক নয়।

গ) Although he laziness, he passed the exam.
"he laziness" বাক্যে ভুল; "laziness" noun, এর সাথে subject + verb লাগবে।
সঠিক হবে: "Although he was lazy" বা "Although he had laziness"।
এই বাক্য ব্যাকরণগতভাবে ভুল।

ঘ) Despite he was lazy, he passed the exam.
"Despite" এর পর কারেক্ট ফর্ম হলো noun, pronoun বা gerund, আবার পুরো clause এর ক্ষেত্রে হলে "Despite the fact that" বা "Although" ব্যবহার হয়।
"Despite he was lazy" ভুল।

Source: A Passage to the English Language by S M Zakir Hussain.