Excel Formula Expert

Act as an Advanced Excel Expert. I need a single formula to solve this problem.

Data Structure:

• Column A: Date
• Column B: Salesperson Name
• Column C: Region
• Column D: Sales Amount

Goal: Sum the total sales for 'John Doe' in the 'North' region, but only for the month of January 2026.

Constraints:

• Do not use Pivot Tables.
• Use modern array functions if applicable (like FILTER or SUMIFS).
• Explain how the syntax works step-by-step.