Under what conditions is a left turn on red sometimes permitted in Ohio?

Answer: C — From a one-way street onto a one-way street

In Ohio, a left turn on red is only permitted when both streets involved are one-way streets. Options A and B are incorrect because they involve at least one two-way street. Option D is incorrect because it states that all turns on red are prohibited, which is not the case in Ohio. Making a left turn on red is only allowed in certain situations, specifically when both streets involved are one-way.