Calculate max rectangle area of a matrix of 0 and 1s

MaxRectangleFinder.cs

using System;
					
public class Program {
	public static void Main() {
		var matrices = new []{
			new [] {
				"00000",
				"00000",
				"00000",
				"00000",
				"00000"
			},
			new [] {
				"10000",
				"00000",
				"10000",
				"10000",
				"00000"
			},
			new [] {
				"11011",
				"01101",
				"11110",
				"11111",
				"01111"
			},
			new [] {
				"101101",
				"111111",
				"011111",
				"111111",
				"001111",
				"011111"
			}
		};

		foreach(var matrix in matrices) {
			int maxArea = CalculateMaxRectangleArea(matrix);
			Console.WriteLine($"The max rectangle area is {maxArea}");
		}
	}
    
	static int CalculateMaxRectangleArea(string[] matrix) {
		int maxArea = 0, loopCounter = 0;
		for (int i = 0; i < matrix.Length; i++) {
			for (int j = 0; j < matrix[i].Length; j++) {
				int maxVerticalExtend = matrix.Length - i;
				for (int horizontalExtend = 0; j + horizontalExtend < matrix[i].Length; horizontalExtend++) {
					int verticalExtend = 0;
					for (; verticalExtend < maxVerticalExtend; verticalExtend++) {
						loopCounter++;
						if (matrix[i + verticalExtend][j + horizontalExtend] == '0') // Not every cell is 1, we break out prematurely
							break;
						int area = (horizontalExtend + 1) * (verticalExtend + 1);
						if (area > maxArea)
							maxArea = area;
					}
					maxVerticalExtend = verticalExtend;
				}
			}
		}
		
		Console.WriteLine($"The loop count is {loopCounter}");
		return maxArea;
	}
}