Write a function that returns the sum of all elements in a 2D array using nested for loops. The function should take a 2D array and its dimensions as parameters, use nested loops to iterate through all elements, calculate the sum, and return it as an integer.

• The function should accept a 2D array of integers, the number of rows, and the number of columns as parameters.
• Use nested for loops to access every element of the array.
• Add each element's value to a running total.
• Return the total sum as an integer.