To determine which group of individuals cannot cast their votes remotely through the postal ballot system in India, it's essential to understand who the Indian electoral provisions allow to use this facility. The postal ballot system is primarily intended for certain groups that cannot vote in person at their designated polling stations due to their service obligations or other constraints. These groups include:
- Members of the armed forces (Army, Air Force, and Navy): They are provided with the postal voting facility given their deployment across various locations.
- Government employees posted outside India: They are eligible to vote by postal ballot owing to their official assignments abroad.
- Voters under preventive detention: These voters are allowed to vote via postal ballot as they cannot physically access polling stations.
However, government employees serving outside their state do not fall under the category eligible for postal voting. The postal ballot system is primarily intended for those dealing with national security, foreign services, or detention scenarios, thereby excluding state-based government employees. Therefore, the correct answer is:
Government employees serving outside their state