What is the location and function of the notochord?

What are the Chordates and non-chordates?

Fishes,amphibians,reptiles,and birds are kept in the same

Which one of the following features are true for chordates?
$(a)$ Heart is ventral.
$(b)$ Pharyngeal gill slits present.
$(c)$ Central nervous system is ventral,solid and single.
$(d)$ Post-anal tail is present.
$(e)$ Notochord is present.
Choose the most appropriate answer from the options given below:

Select the correct statements with reference to chordates.
$A$. Presence of a mid-dorsal,solid and double nerve cord.
$B$. Presence of closed circulatory system.
$C$. Presence of paired pharyngeal gill slits.
$D$. Presence of dorsal heart.
$E$. Triploblastic pseudocoelomate animals.
Choose the correct answer from the options given below:

On which side of the body is the notochord located in chordates?