Concept:Unrhymed iambic pentameter lines illustrate the verse form known as blank verse.
Explanation:Iambic pentameter is a metrical pattern with five iambs in each line, where an iamb is an unstressed syllable followed by a stressed syllable.
When these lines follow the regular metre but do not rhyme with one another, they are called blank verse.
This form is common in English drama and poetry because it closely mimics the natural rhythm of speech.
Free verse, on the other hand, has no fixed metre or regular rhythmic pattern, so it is not the correct description here.
A heroic couplet would require paired rhyming lines in iambic pentameter, while a rhyme scheme depends on recurring end sounds, both of which are absent from unrhymed lines.
Answer:C. blank verse