“তারা যতই চেষ্টা করুক, সফল হতে পারবে না।”

• Correct Answer: খ) No matter how hard they try, they won’t succeed.

- “যতই চেষ্টা করুক” → No matter how hard they try.
- “পারবে না” = won’t succeed.
- Perfect future-tense structure, idiomatic and grammatically natural.
- “তারা যতই চেষ্টা করুক, সফল হতে পারবে না।”
- No matter how hard they try, they won’t succeed.

• Other options:
ক) However they try, they cannot succeed.
- সঠিক অনুবাদ নয়।
- "However they try" is not a common idiomatic form.

গ) Though they try, they didn’t succeed.
- Tense দুই ধরণের ব্যবহার হয়েছে - “try” is present, “didn’t” is past.

ঘ) Though they will try, they won’t succeed.
- Grammatically সঠিক নয় "though they will try" is not idiomatic; better expressed with “even if” or “no matter how”.

Source: Merriam-Webster Dictionary, Accessible Dictionary, Cambridge Dictionary.