By which developmental similarity are Echinoderms related to Chordates?

Given below are two statements: one is labelled as Assertion $(A)$ and the other is labelled as Reason $(R)$.
Assertion $(A):$ All vertebrates are chordates but all chordates are not vertebrates.
Reason $(R):$ The members of subphylum Vertebrata possess a notochord during the embryonic period; the notochord is replaced by a cartilaginous or bony vertebral column in adults.
In the light of the above statements,choose the correct answer from the options given below:

Draw a labeled diagram showing the fundamental characteristics of Phylum Chordata.

In which of the following animals is a post-anal tail found?

Protochordates lack which of the following?

Branchiostoma belongs to