. . . . . . . . further you go, . . . . . . . . more tired you will be. A. the, the B. a, the C. an, a D. the, a

the, the
a, the
an, a
the, a

The correct answer is: A. the, the

The reason is that the sentence is about a general trend, not a specific instance. In other words, it is saying that the more you go, the more tired you will be, regardless of who you are or where you are going. This makes it a good use of the definite article “the.”

The other options are not as good because they are more specific. For example, option B, “a, the,” would imply that there is a specific person or place that is more tiring than others. Option C, “an, a,” would imply that there is a specific type of activity that is more tiring than others. And option D, “the, a,” would imply that there is a specific time of day or year that is more tiring than others.

In conclusion, the correct answer is A. the, the because it is the most general option and it best reflects the meaning of the sentence.