Question

B) the important deviation it makes and reasons for the same with reference to the IDL.

Answer 1

The International Date Line (IDL) is an imaginary line of longitude on the Earth's surface located at about 180 degrees east (or west) of the Greenwich Meridian. The date line is shown as an uneven black vertical line in the Time Zone Map above and marks the divide where the date changes by one day.
In 1519, Ferdinand Magellan set out westward from Spain, sailing for East Asia with 241 men in five ships. Three years later, the remnants of his crew (18 men in one ship) successfully completed the first circumnavigation of the globe. Although a careful log had been kept, the crew found that their calendar was one day short of the correct date. This was the first human experience with time change on a global scale, the realization of which eventually led to the establishment of the International Date Line.