Which of the following is not true regarding the structure of RNA?
a. RNAs with extended regions of base-pair complementarity adopt a helical form identical to B-type DNA.
b. The ribose ring has a hydroxyl (-OH) group on its 2' carbon.
c. Bases in RNA can form non-Watson-Crick base pairs.
d. Base-pairing between short complementary sequences can fold a single-stranded RNA into a stable 3-dimensional structure.
e. RNA does not form adenine-thymine (A-T) base pairs.