unsupervised

The assign-then-update loop is ten lines; the signal is whether you handle the three things that bite in production: initialization, an empty cluster, and a real convergence test instead of a fixed iteration count.

Unsupervised questions filter out candidates who've only done Kaggle. The elbow method is the warm-up, the real scoring is on validation without labels and the marketing-team handoff.

Almost no labels means you cannot train a classifier and you cannot honestly report recall. The senior answer is to score by typicality, threshold by the customer's review budget, and build the labeling flywheel that turns this into a supervised problem within two quarters.