Let's evaluate each sentence for grammatical correctness:
A. "My family adopted a dog that is a Dalmatian and retrieve her mix."
- Incorrect: The phrase "retrieve her mix" seems to have a typographical error. It should likely say "and retriever mix." The correct version would be: "My family adopted a dog that is a Dalmatian and retriever mix."
B. "I need shoes which are more comfortable for the marathon."
- Correct: While "which" is commonly used in British English, "that" is often preferred in American English for defining clauses. However, both are acceptable, and the sentence is grammatically correct.
C. "The clothes, which are dirty, well I'll fit in the washing machine."
- Incorrect: The phrase is poorly constructed. It should be edited for clarity. A better version might be: "The clothes, which are dirty, will fit in the washing machine."
D. "My cat, that mostly stays outside, climbs on the window when she wants to come inside."
- Incorrect: The word "that" is not used correctly here; it should be "which" for non-defining clauses. The correct version would be: "My cat, which mostly stays outside, climbs on the window when she wants to come inside."
In summary, (B) is correct, while (A), (C), and (D) require revisions to be correct.