What is the correct answer?
4
A. A-Notochord; B-Post-anal part; C-Gill slits; D-Nerve cord
B. A-Nerve cord; B-Notochord; C-Post-anal part; D-Gill slits
C. A-Notochord; B-Nerve cord; C-Gill slits; D-Post-anal part
D. A-Gill slits; B-Post-anal part; C-Nerve cord; D-Notochord