Distinct Campaigns per Region (Array Formula)

You're a marketing analyst pulling a "distinct campaigns per region" metric for tomorrow's ops review. The campaign-execution log at A2:B25 records (Region, Campaign Name) for every send — and the same campaign typically runs multiple times per region across the quarter, so the table has heavy duplication.

You need the count of distinct campaign names for each of the three target regions in D2:D4.

This is a classic "uniques per group" problem. Two acceptable approaches:

• Modern (Excel 365 / 2021+): COUNTA(UNIQUE(FILTER(...))) — filter to the target region, dedupe, count.
• Legacy array trick: SUMPRODUCT(($A$2:$A$25=D2) / COUNTIFS($A$2:$A$25, D2, $B$2:$B$25, $B$2:$B$25)) — for every row in the target region, contribute one over the count of (target region, that campaign) combos. Each unique campaign sums to 1; duplicates split into fractions that recombine to 1.

Wrap the legacy version in IFERROR(..., 0) to swallow the #DIV/0! from non-target rows.

Your task:

1. In E2:E4, write a formula that returns the distinct campaign count for each target region in D2:D4.
2. Either approach above is acceptable; the grader checks the integer count, not the formula shape.

Graded cells: E2, E3, E4.