I look forward to____
have heard from you soon
see you soon.
hear for you soon.
hearing from you soon
Explanation:
Correct Answer is: hearing from you soon
I look forward to hearing from you soon
With a view to, look forward to, accustomed to, addicted to, be/get used to ইত্যাদি phrase গুলোর পর সর্বদা মূল verb – এর সাথে ing যুক্ত হয়।