Let P and Q be proposition symbols. Which of the following are literals and which are

sentences? fill in the blank next to each item using the code

provided.

$$ L $=$ is a literal but not a sentence

$$ S $=$ is a sentence but not a literal

$$ B $=$ is both a literal and a sentence

$$ N $=$ is neither a literal nor a sentence

$($a$)$ P

$($b$)$Q

$($c$)$ P $$ Q

$($d$)$ P $$Q

$($e$)$ P $|=$ Q