The correct answer is D. 7th.
Bihar ranks 7th in terms of road network density as per Economic Survey 2018-19. The state has a road network density of 10.4 km per 100 sq km. This is lower than the national average of 16.2 km per 100 sq km.
The road network in Bihar is in a poor condition. Many roads are narrow and unpaved. This makes it difficult for people to travel and transport goods. The poor condition of the roads also leads to accidents.
The government of Bihar has taken some steps to improve the road network in the state. It has started a project to build new roads and to improve the condition of existing roads. However, more needs to be done to improve the road network in Bihar.
Option A is incorrect. Bihar does not rank 1st in terms of road network density. The state ranks 7th.
Option B is incorrect. Bihar does not rank 3rd in terms of road network density. The state ranks 7th.
Option C is incorrect. Bihar does not rank 5th in terms of road network density. The state ranks 7th.