In which of the following activities are Indian Remote Sensing (IRS) satellites used? 1. Assessment of crop productivity 2. Locating groundwater resources 3. Mineral exploration 4. Telecommunications 5. Traffic studies Select the correct answer using the code given below.

Indian Remote Sensing (IRS) satellites are Earth Observation satellites designed for natural resource management, enabling the assessment of crop productivity, groundwater mapping, and mineral exploration through multi-spectral imaging. Telecommunications (Option 4) is handled by communication satellites like the INSAT/GSAT series, while traffic studies (Option 5) typically rely on navigation satellites (IRNSS/NavIC) or ground-based sensors rather than remote sensing. The core concept tested is the functional distinction between different types of satellite systems (Remote Sensing vs. Communication/Navigation) and their specific orbital applications.