All will go _______ Karachi _______ April.

All will go _______ Karachi _______ April.

Explanation

"All will go to Karachi in April."


  • "To" is used for direction or destination go to Karachi.

  • "In" is used for months, years, and longer periods → in April.

 So, the correct and natural usage is: to Karachi, in April.