Option A: It is an example of a positive externality.

Option B: It is an example of a positive externality.

Option C: It is an example of a positive externality.

Option D: The development of weapons of mass destruction is an example of a negative externality associated with the government support of education. The government provides with funds to educate more and more citizens and empower a country with its human resource. Some students might make use of this education in such a way that it adversely affects the welfare of the country. It may be in the form of increased criminal activities, black marketing, and other such activities. Thus, the development of weapons will create a state of unrest in the world as a whole.