Concept:
The Model Regional and Town Planning and Development Law was prepared to provide a uniform legal framework for planned urban and regional development in India.
The law aimed to:
• Guide urban development
• Regulate land use
• Promote planned regional growth
• Assist states in preparing planning legislation
Step 1: Analyze ITPI.
ITPI (Institute of Town Planners, India) is a professional body of planners but did not enact the model planning law.
Hence, option A is incorrect.
Step 2: Analyze TCPO.
TCPO (Town and Country Planning Organisation) prepared and introduced the Model Regional and Town Planning and Development Law in 1985.
Hence, option B is correct.
Step 3: Analyze HUDCO.
HUDCO mainly finances housing and urban infrastructure projects.
Hence, option C is incorrect.
Step 4: Analyze NGT.
NGT (National Green Tribunal) deals with environmental cases and was established much later.
Hence, option D is incorrect.
Step 5: Choose the correct option.
The organisation responsible for the Model Regional and Town Planning and Development Law, 1985, was TCPO.
Therefore, the correct answer is:
\[
{\text{(B) TCPO}}
\]