Final answer:
The thesis statement is sentence D, which is sentence 5 in the passage, asserting that quality day care is available with proper investigation.
Step-by-step explanation:
The thesis statement in the passage provided is sentence D, sentence 5: "But good day care is available if parents take the time to investigate." This serves as the thesis because it introduces the main argument or claim of the text — that while parents may feel guilty about not being able to stay home with their children, quality day care can be found with proper investigation. It sets the stage for the subsequent discussion about the characteristics of a good child care center, addressing concerns of cleanliness, safety, and staff qualifications that are vital for day care centers to be considered beneficial options for children's care.