Chapter 14, Problem 14.53P

a. How many signals does dimethyl fumarate $\left({\text{CH}}_{\text{3}}{\text{O}}_{\text{2}}\text{CCH}={\text{CHCO}}_{\text{2}}{\text{CH}}_{\text{3}}\text{, with a trans C}=\text{C}\right)$ exhibit in its ${}^{\text{13}}\text{C}$ NMR spectrum?

b. Draw the structure of an isomer of dimethyl fumarate that has each of the following number of signals in its ${}^{\text{13}}\text{C}$ NMR spectrum: [1] three; [2] four; [5] five.