Which of the following missiles was jointly developed by India and Russia as a supersonic cruise missile used by the armed forces?

Introduction / Context:
India has developed several missile systems, some purely indigenous and some in partnership with other countries. A very famous example of international collaboration is a supersonic cruise missile project jointly undertaken by India and Russia. This question checks whether you can identify that joint venture missile correctly from among well known Indian missile names.

Given Data / Assumptions:

- The missile in question is a supersonic cruise missile, not a ballistic missile.

- It was developed through cooperation between India and Russia.

- The options list different types of Indian missiles: Agni, Prithvi, BrahMos, and Akash.

Concept / Approach:
Agni and Prithvi are primarily indigenous ballistic missile series developed under India's Integrated Guided Missile Development Programme. Akash is an indigenous surface to air missile system. BrahMos, however, is a joint venture between India and Russia, combining names of the Brahmaputra and Moskva rivers. It is a supersonic cruise missile capable of being launched from land, sea, and air platforms. Therefore, the only option that matches all the conditions in the question is BrahMos.

Step-by-Step Solution:
Step 1: Note that the missile must be a cruise missile, not a ballistic missile, and that it should be a joint project between India and Russia. Step 2: Recall that the Agni series consists of long range ballistic missiles developed by India without a Russian joint venture label. Step 3: Recall that Prithvi is also a ballistic missile used primarily as a short range surface to surface system developed indigenously. Step 4: Recognise that Akash is a surface to air missile designed mainly for air defence and is again an Indian project. Step 5: Identify BrahMos as a supersonic cruise missile produced by an Indo Russian joint venture company and deployed by the Indian armed forces. Step 6: Conclude that the correct option is BrahMos supersonic cruise missile.

Verification / Alternative check:
Official information from the joint venture company and defence ministry statements describe BrahMos as a product of Indo Russian cooperation, with design inputs from both sides. It is widely reported as one of the fastest operational cruise missiles in its class. In contrast, Agni, Prithvi, and Akash are consistently described as Indian missile systems originating under the Integrated Guided Missile Development Programme without a joint naming structure linked to Russia. This cross checking confirms that BrahMos uniquely satisfies the conditions given in the question.

Why Other Options Are Wrong:
The Agni series, though vital for strategic capability, is a set of ballistic missiles and does not involve a joint naming structure with Russia. Prithvi is also part of the indigenous ballistic missile family and does not count as a joint Indo Russian supersonic cruise missile. Akash is an Indian made surface to air missile used for air defence, not a cruise missile co developed with Russia. Thus, these options may seem important but do not match the full description of the missile mentioned in the question.

Common Pitfalls:
Sometimes candidates focus only on the fame of a missile name and forget to check whether it is ballistic or cruise, or whether it is jointly developed. Others confuse Akash or Agni with BrahMos because all are often mentioned together in discussions of Indian missile power. The best way to avoid mistakes is to remember the unique features of BrahMos: Indo Russian joint venture, supersonic speed, and cruise missile category.

Final Answer:
The missile jointly developed by India and Russia as a supersonic cruise missile is the BrahMos supersonic cruise missile.