What is the location and function of pharyngeal gill slits?

Which of the following is not a fundamental character of the phylum $Chordata$?

Which of the following is described as a protochordate?

Which of the following is a characteristic feature of $Phylum-Chordata$?

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:

Differentiate between Non-Chordata and Chordata.