Which situations involve a cell using endocytosis?
1. A cell wraps a portion of its membrane around a droplet of nutrient‑rich water and brings the droplet inside the cell.
2. Water moves across a cell membrane and into a cell through specialized protein tunnels in response to a concentration gradient.
3. Digestive enzymes are disgorged into the small intestine through the cell membrane of the cell in which they were produced.
4. A free‑living single‑celled organism engulfs a smaller single celled organism and uses the smaller organism as a food source.
5. LDL cholesterol attaches to cell membrane proteins, triggering the membrane to fold around the cholesterol and bring it into the cell.

Endocytosis is a process in which the substances are brought inside the cell. The material to be internalized inside the cell is surrounded by the cell membrane, it is bud off inside the cell. The material forms the vesicle of ingested material.

Option 1 is the situation which describes the endocytosis. The cell membrane surrounds the nutrient rich water and brings the droplet inside the cell hence favors endocytosis.