Explanation:

- Start with identifying relationships:

- C is the husband of F, making them a married couple and establishing F as a woman.

- D is the daughter of B.

- E has only one daughter, making E the father of D and husband to B.

- C is the son of A, confirming A as C's parent.

- E is the brother-in-law of G, making G the wife of A.

- B is the spouse of E, confirming B as a woman and a part of one of the married couples.

- As C is the son of A and grandson of E, A must be the child of E, hence A is E's daughter.

- B is the mother of A, making B the mother-in-law of A.

- Therefore, ? Option 4: B is the mother-in-law of A.

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