Which sentence uses capitalization correctly?

(A)In class, I learned that two-thirds of egypt is covered by part of the huge Sahara Desert that stretches across africa.

(B)In class, I learned that two-thirds of Egypt is covered by part of the huge Sahara Desert that stretches across Africa.

(C)In class, I learned that two-thirds of Egypt is covered by part of the huge sahara desert that stretches across Africa.

(D)In class, i learned that two-thirds of Egypt is covered by part of the huge Sahara Desert that stretches across Africa.