Three pairs missed an easy game here.

South and West are Passing. North will open 1♦ unless playing a very rare 16-18 No Trump or a rare (at this Club) Strong Club (Precision, Blue Club, or Nottingham Club).

East is Passing and South has to bid 1♠ to show the 4-card Major. West has to Pass.

North is rebidding 2NT. Whether you play a weak NT, a Strong NT, or Benji the sequence 1♦ - 1♠ -2NT includes a balanced 18 count in it's range.

South adds their 10HCP to the points they know North holds and immediately knows thay have more than the 25 points required for game in No Trumps.

South therefore has to bid 3NT.