Dun is to gray-beige, as stanza is to

ballad
elegy
sonnet
verse

Dun and Gray-beige are quite similar colors,  

Analyzing the meaning of stanza and the four options that are given

Dun is to gray-beige, as stanza is to verse

Stanza is a group of sentences forming a verse more specifically a group of 4 lines

Ballad is a complete poem telling a story in stanzas

Elegy is a sad poem that expresses sorrow and is normally inspired by a dead person

Sonnet is a poem made with 14 lines that not necessarily works with stanzas

Verse is a group of four stanzas.

since he could see color, and nobody else could, he didn't find it fair that everyone else in the utopia couldn't see color but him and the giver : d