Correct option is B
Indra I and Indra II are radar systems developed by India's DRDO (Defence Research and Development Organisation) for the Indian Army and Air Force. These are part of the Indian Doppler Radar series.
Indra I is a mobile surveillance radar designed for detecting low-level targets, primarily aircraft flying at low altitudes.
Indra II is an advanced radar used for ground-controlled interception of targets. It has additional features like pulse compression and is capable of handling heavy ground clutter, making it suitable for detecting low-flying aircraft.
