What does a sign with a picture of a bicycle inside a white square with a red border indicate?

Answer: B — Bicycles prohibited on the road.

A sign with a picture of a bicycle inside a white square with a red border usually indicates that bicycles are prohibited on the road. The red border is a common symbol for prohibited activities, and the picture of the bicycle clearly suggests that bikes are not allowed in that area. Option A, bike lane ends ahead, is incorrect because a sign indicating the end of a bike lane would typically have a black and white striped border. Option C, bicycle parking area ahead, is also incorrect because the sign for a bike parking area would likely have a different image, such as a bicycle leaning against a pole. Option D, no bicycles allowed, is similar to the correct answer, but the use of "no" instead of "prohibited" could be confusing. Therefore, the correct answer is B Bicycles prohibited on the road.