Which of the following best describes the stereochemistry of ring closure and the product for the chemical reaction below?
a. disrotatory, cis-5.6-diethyl-1,3-cyclohexadiene
b. conrotatory, cis-5,6-diethyl-1,3-cyclohexadiene
c. disrotatory, trans-5,6-diethyl-1,3-cyclohexadiene
d. conrotatory, trans-5,6-diethyl-1,3-cyclohexadiene