Determiners are words that are used to introduce and modify nouns. They help provide information about the quantity or specificity of the noun they precede. In this case, we need to choose an appropriate determiner to complete the sentence "________ philosophy is concerned with life after death."

Determiners can be categorized into different types such as definite and indefinite articles, demonstratives, quantifiers, possessives, and numbers. Each type serves a specific purpose in providing information about the noun.

In this particular sentence, we need a determiner that indicates a general or non-specific philosophy. Let's analyze the options given:

a) Much
b) Much of
c) Either could be used here

- Much: This determiner is used to indicate a large quantity or amount. However, it does not fit well in the context of the sentence. Using "much" would imply that there is a large quantity of philosophy concerned with life after death, which does not make sense in this context.

- Much of: This determiner phrase is used to refer to a large part or a significant amount of something. It is more appropriate in this context as it suggests that a significant portion of philosophy is concerned with life after death.

- Either could be used here: This option implies that both "much" and "much of" are equally suitable in this context, but it is not correct. While "much of" is the appropriate determiner in this sentence, "much" on its own does not convey the intended meaning.

Therefore, the correct answer is option B: Much of philosophy is concerned with life after death.