The correct answer is option 'C' - Amravati.

Explanation:
River Krishna, one of the major rivers in India, flows through the states of Maharashtra, Karnataka, Telangana, and Andhra Pradesh. It is formed by the confluence of five rivers - Darna, Varna, Koyna, Bhima, and Amarja. The river Krishna has several tributaries that contribute to its water flow and drainage system.

Let's analyze each option to identify the tributaries of river Krishna:

a) Tungabhadra: Tungabhadra is a tributary of river Krishna. It originates in the state of Karnataka and flows through the districts of Bellary and Kurnool. It joins the river Krishna near Alampur in Telangana.

b) Malaprabha: Malaprabha is another tributary of river Krishna. It originates in the Western Ghats of Maharashtra and flows through the state of Karnataka. It joins the river Krishna near the town of Kudalasangama.

c) Amravati: Amravati is not a tributary of river Krishna. It is a city in Maharashtra, but it does not contribute to the water flow of the river Krishna.

d) Ghataprabha: Ghataprabha is also a tributary of river Krishna. It originates in the Western Ghats of Karnataka and flows through the districts of Belagavi and Vijayapura. It joins the river Krishna near the town of Chikodi.

In conclusion, among the given options, Amravati is not a tributary of river Krishna.