Answer:
A. unrhymed lines of iambic pentameter.
Step-by-step explanation:
Blank verse is a literary device which describes unrhymed lines of iambic pentameter. This means that blank verse has a consistent meter of 10 syllables per line, in which each unstressed syllable is followed by a stressed syllable. Poetry written in blank verse has no fixed number of lines. Moreover, it can be composed in any kind of meter, such as iamb, trochee, spondee, and dactyl.