Which of the following sentences with a parenthetical expression is punctuated correctly? Select one:
a. Oil paintings in my opinion, are unmatched in their ability to portray movement and energy.
b. Cave paintings, in fact, are proof that the urge to create has always been part of what makes us human.
c. Watercolor, unlike oil paint has a transparency that reflects light back up from the canvas.
d. The fumes from oils and acrylics on the other hand, made Bob sneeze.