Explanation: Longitude lines are a fundamental part of the geographic coordinate system used to pinpoint locations on the Earth's surface. These lines run from the North Pole to the South Pole and are perpendicular to the equator. The Prime Meridian, which is located at 0o longitude, passes through Greenwich, England, and serves as the reference point for measuring longitude.
Longitude is measured in degrees east (E) and west (W) of the Prime Meridian. The Earth is divided into 360 degrees of longitude, with 180 degrees to the east and 180 degrees to the west of the Prime Meridian. The westernmost longitude of India is 68o7'E, which is located in the state of Gujarat. This line marks the western boundary of India in terms of longitude, indicating the furthest west point of the country.
It is important to understand that the westernmost longitude is measured in degrees east (E) because the Prime Meridian is the reference point, and all longitudes to the east of it are positive. The confusion often arises when students mix up the direction of measurement, thinking that the westernmost point should be measured in degrees west (W). However, since the Prime Meridian is the starting point, the westernmost longitude of India is still measured in degrees east, but it is the smallest positive value among all the longitudes that pass through India.
In the context of the options provided, option A is the correct answer because it correctly identifies the westernmost longitude of India as 68o7'E and specifies that it is located in Gujarat. The other options are incorrect because they either use the wrong direction (north or south) or the wrong location (Mumbai instead of Gujarat).
Understanding the concept of longitude and its measurement is crucial for various fields, including geography, navigation, and cartography. It helps in accurately locating places on the Earth's surface and is essential for mapping and spatial analysis.