In December 2016, India signed an agreement with which country to assist in green and sustainable construction of infrastructure in the Himalayan kingdom?

Introduction / Context:
This question tests your awareness of India's relations with neighbouring countries, especially small Himalayan kingdoms where India provides developmental assistance. It refers to an agreement focused on green and sustainable construction of infrastructure, reflecting growing concern for environmentally friendly development.

Given Data / Assumptions:

• The agreement was signed in December 2016.
• The purpose was assistance in green and sustainable construction.
• The partner country is described as a Himalayan kingdom.
• Options include Nepal, Afghanistan, Bhutan and Pakistan.

Concept / Approach:
The key idea is to correctly associate the phrase Himalayan kingdom with the appropriate country. Among the options, Bhutan is widely described as a Himalayan kingdom and is a close partner of India in hydropower, infrastructure and environmental cooperation. Nepal is a Himalayan country but is usually described as a federal democratic republic, not a kingdom after the end of monarchy. Afghanistan and Pakistan are not referred to as Himalayan kingdoms. Therefore, the combination of time period, project nature and description points towards Bhutan.

Step-by-Step Solution:
Step 1: Identify which of the listed countries can be accurately called a Himalayan kingdom. Step 2: Recall that Bhutan is a small Himalayan kingdom located between India and China. Step 3: Remember that India has multiple cooperation programmes with Bhutan, including hydropower and green infrastructure. Step 4: Note that Nepal, although Himalayan, had abolished its monarchy and changed its constitutional status. Step 5: Eliminate Afghanistan and Pakistan as they are not normally labelled Himalayan kingdoms, and select Bhutan.

Verification / Alternative check:
Press releases from December 2016 highlight agreements between India and Bhutan in areas of sustainable infrastructure and green buildings. Bhutan also promotes Gross National Happiness and environmental conservation, making it a natural partner for such green initiatives. These facts confirm that Bhutan is the country mentioned in the question.

Why Other Options Are Wrong:
Nepal: Nepal is a Himalayan country, but the term Himalayan kingdom is not typically used after the monarchy was abolished. Also, the specific December 2016 agreement about green construction refers to Bhutan.

Afghanistan: Afghanistan is a landlocked country in Central and South Asia, not a Himalayan kingdom, and is not the focus of this particular green infrastructure agreement.

Pakistan: Pakistan has mountainous regions but is not known as a Himalayan kingdom, and there was no such December 2016 agreement with India described in these terms.

Common Pitfalls:
A frequent mistake is to choose Nepal simply because it is strongly associated with the Himalayas. However, paying attention to the exact expression Himalayan kingdom and to the time period and nature of the agreement helps narrow the choice to Bhutan.

Final Answer:
India signed the agreement for green and sustainable infrastructure construction with the Himalayan kingdom of Bhutan.