I do not think you will have any difficulty ___ a driving license.

Explanation: Difficulty (noun) - the fact of not being easy to do or understand অর্থাৎ কোনো কিছু করা কষ্টকর বোঝানোর জন্য difficulty in ব্যবহৃত হয় এবং 
নিয়মানুযায়ী difficulty in এর পর verb এর সাথে ing যুক্ত হয়। 
যেমন: difficulty in breathing, difficulty in learning etc.

তাই সঠিক অপশনটি হবে - in getting.
Complete sentence: I do not think you will have any difficulty in getting a driving license.