The correct answer is option 2, which states that the long duration of hot and dry conditions is one of the reasons behind Gujarat being the leading producer of salt in India.

Let`s look at each option to understand why option 2 is the correct choice:

Option 1 suggests that the long length of coastline is a reason for Gujarat being the leading producer of salt. This option is not correct because having a long coastline alone does not guarantee high salt production. There are other factors that come into play.

Option 2 states that the long duration of hot and dry conditions is a reason for Gujarat`s leading salt production. This option is correct. Gujarat experiences a long summer season with high temperatures and low rainfall, creating ideal conditions for the evaporation of seawater and salt production.

Option 3 suggests that the presence of gulf areas is a reason for Gujarat`s salt production. This option is not correct because the presence of gulf areas does not directly contribute to salt production. The presence of gulf areas may have some influence on the climate, but it is not the primary reason for Gujarat`s salt production.

In conclusion, the correct answer is option 2, as the long duration of hot and dry conditions in Gujarat is a significant factor in making it the leading producer