A student has been assigned to write a position paper on the issue of whether writing classes should be required for all college students. Which of the following sentences is the BEST example of an explicit, appropriately qualified thesis statement on this issue?

a$.$

In college writing classes, students learn about communication, rhetoric, and responsible participation in today's world.

b$.$

In many cases, most students would usually benefit from writing classes, but, sometimes, writing classes might not be needed or beneficial, or students might not understand or respond to the information, so writing classes could sometimes be redundant or not applicable.

c$.$

All students must take a writing class as part of their college degree.

d$.$

For most students, writing classes should be required because these classes are valuable for learning about communication, rhetoric, and responsible participation in today's world.