An analogy is a technique used by people to compare or relate one object, statement, or circumstance to another. At its most basic definition, it is a comparisson of two things in order to show their similarities. One of the many forms of using analogies is what is known as word analogies, or verbal analogies, that are often used to compare two objects, often to show their similarities, but that require the use of logic and reasoning to see the connection, as there are only two words being used or compared. In this case, the use of the adjective, blinding, has the effect of linking the concept of light to one of its many characteristics, which is, that it can be blinding. The relationship here is established by the description that blinding makes of Light, which is why the answer is C, degree of intensity.
