The entire science for freezing rows and columns together lies within selecting the right cell before we freeze panes.
To freeze rows and columns together, select the cell that falls in the row and the column immediately after the last row and the last column to be frozen.
In our example, the last column that we want to freeze is Column B. The immediately next column to Column B is Column C.
And the last row that we want to freeze is Row 3. The immediately next row to Row 3 is Row 4.
So we will select Cell C4 (which falls at the intersection of Column C and Row 4) 4️⃣