Molecules which are transported across the membrane against their concentration gradient, i.e. from the lower to higher concentration. Such a transport is called

1. Active transport, e.g., diffusion
2. Passive transport, e.g., diffusion
3. Osmosis, a type of simple diffusion
4. Active transport, e.g., $N{a}^{+}/K^{+}$ pump

The correct option is D Active transport, e.g., $N{a}^{+}/K^{+}$ pump
Active transport

Active transport is movement of molecules against the concentration gradient i.e. from lower to higher concentration. Active transport needs $ATP.N{a}^{+}/K^{+}$ pump works actively and is present in the cell membrane.

Final answer:

(C) Active transport, e.g., $N{a}^{+}/K^{+}$ pump