Looked pretty.
a. 
the girl in blue
b. 
turn right
c. 
on the field
d. 
before sunset
e. 
since then

A) The girl in blue

Explanation:

Answer choice B is describing an action, answer C needs something before that describes what's on the field, answer D needs another explanation, answer E needs an "it" after the answer for it to make sense with "...looked pretty".

So answer A is the only correct answer.

postive, comparative, superlative - good, better, best

recall how we defined nouns as words capable of having plurals and possessive endings. adjectives (and their first cousin, the adverb) also have a feature that distinguishes them. they come in three states. first, the raw adjective—in its positive state—merely describes the noun modified; it doesn’t care about how this particular person or thing stacks up against other members of the same noun class