X introduces Y saying, "He is the husband of the granddaughter of the father of my father." How is Y related to X?

Introduction / Context:
This problem involves three generations and then adds a spouse on top of that. It is a typical exam pattern where you must carefully understand phrases like "father of my father" and "granddaughter" and then see how the husband of that person fits into your own family from the speakers point of view.

Given Data / Assumptions:

• X is speaking and introducing Y.
• X says, "He is the husband of the granddaughter of the father of my father."
• "Father of my father" is X grandfather on the paternal side.
• "Granddaughter of the father of my father" refers to any granddaughter of that grandfather.
• We assume standard family structures and that the exam expects the most natural and common relation from the options given.

Concept / Approach:
We first identify the central ancestor, then list who can be called a granddaughter of that person, and finally attach a husband to such a granddaughter. That husband relation is what Y has with X. For the phrase "granddaughter of the father of my father", natural candidates for that granddaughter are X sisters or female cousins from the grandfather other children.

Step-by-Step Solution:
Step 1: The "father of my father" is X grandfather.Step 2: Any granddaughter of this grandfather must be a female person in the generation of X. She could be X herself if X is female, or X sister, or a female cousin who is the daughter of one of X uncles or aunts from that grandfather line.Step 3: The sentence says that Y is the husband of such a granddaughter. Thus Y is married to a woman who is in the same generation as X and is a granddaughter of X grandfather.Step 4: From X perspective, if that granddaughter is X herself, then Y would be X husband. If the granddaughter is X sister, Y is X brother-in-law. If the granddaughter is X cousin, Y is still treated socially and in exam language as a brother-in-law.Step 5: Among standard reasoning questions and the given options, the relationship most consistently fitting is that Y is the brother-in-law of X.

Verification / Alternative check:
Consider a typical case where the granddaughter in question is X sister. Let the grandfather be G. G has a son F who is X father, and a daughter A who is X aunt. X and his sister S are children of F. S is clearly a granddaughter of G. If Y is the husband of S, then for X, Y is his brother-in-law. If instead the granddaughter is the daughter of the aunt A, she is X cousin. Y would still be the husband of a female from the same generation, again commonly treated as brother-in-law in such exam questions.

Why Other Options Are Wrong:
Y cannot be X son-in-law, because that would require Y to be married to X daughter, who would be a great granddaughter of X grandfather, not a granddaughter. Y is not X real brother because there is no information that they share parents. Son or uncle also do not fit, as being the husband of a granddaughter places Y in the same generation as X, not above or below.

Common Pitfalls:
Learners sometimes mix up generation levels and treat the granddaughter as if she were a daughter of X, which leads to the wrong choice "son-in-law". Always count generations: grandfather, parent, self, child correspond to four levels. A granddaughter of your grandfather is in your own generation, not your daughters generation. Keeping track of levels avoids such confusion.

Final Answer:
Y is related to X as a brother-in-law.