Direction: Read the information given below and answer the questions.
(i) In a family of six persons $\text{A, B, C, D, E}$ and $\text{F}$, there are two married couples.
(ii) $\text{D}$ is grandmother of $\text{A}$ and mother of $\text{B}$.
(iii) $\text{C}$ is wife of $\text{B}$ and mother of $\text{F}$.
(iv) $\text{F}$ is grand daughter of $\text{E}$.

Which of the following is necessarily true?

Let us systematically chart out the family hierarchy based on the clues:
1. From (ii) and (iii): $\text{D}$ is the mother of $\text{B}$. $\text{B}$ is married to $\text{C}$ ($\text{C}$ is the wife, so $\text{B}$ is the husband). This gives us our first married couple: $\text{B}(+)$ and $\text{C}(-)$.
2. From (iii), $\text{C}$ is the mother of $\text{F}$ ($\text{F}$ is female since she is a granddaughter). Since $\text{D}$ is the grandmother of $\text{A}$ and mother of $\text{B}$, $\text{A}$ and $\text{F}$ are siblings (children of $\text{B}$ and $\text{C}$).
3. From (iv), $\text{F}$ is the granddaughter of $\text{E}$. Since $\text{D}$ is her paternal grandmother, $\text{E}$ must be her paternal grandfather. This gives us our second married couple: $\text{E}(+)$ and $\text{D}(-)$.

Let's look closely at the children of $\text{B}$ and $\text{C}$, who are $\text{A}$ and $\text{F}$:

* $\text{F}$ is confirmed to be female ($\text{granddaughter}$).
* The gender of $\text{A}$ is not specified anywhere in the statements. $\text{A}$ could be male or female.

Reviewing options:

* \text{OPT_A}: Not necessarily true, because $\text{A}$ could be a sister of $\text{F}$.
* \text{OPT_B}: Not necessarily true, because $\text{A}$ 's gender is unknown.
* \text{OPT_C}: Not necessarily true, because $\text{A}$ could be a son.
* \text{OPT_D}: Correct, since none of the specific statements are absolute truths.