03. Grammar

Here is a grammar, specified in a simple notation known as Backus-Naur Form or BNF ^[1]:

S → 0 S 0

S → 1 S 1

S → 00

S → 11

Which of the following sentences are valid according to this grammar?

^[1] For a quick review, check out this brief segment on grammars from our Intro to Computer Science course.