The correct answer is option 2: Desert, Tropical thorny, Moist deciduous, Mangrove.

As you travel from Bikaner to Konark by the shortest distance, you will encounter different types of vegetation along the way. The first type of vegetation you will come across is the desert vegetation. This is because Bikaner is located in the Thar Desert region, which is known for its arid climate and sparse vegetation.

Continuing on the journey, you will then pass through areas with tropical thorny vegetation. This type of vegetation is characterized by thorny shrubs and trees that can withstand dry and arid conditions.

Moving further, you will encounter moist deciduous vegetation. This type of vegetation is found in areas with a moderate amount of rainfall and consist of trees that shed their leaves during the dry season.

Finally, as you near the destination, you may encounter mangrove vegetation. Mangroves are commonly found in coastal areas and are adapted to survive in saline and waterlogged conditions.

To summarize, as you travel from Bikaner to Konark by road, you will encounter a succession of vegetation types including desert, tropical thorny, moist deciduous, and possibly mangrove vegetation.