The correct answer is A. Ten syllables divided into pairs of unstressed and stressed syllables
Step-by-step explanation:
In poetry, verses are composed of rhythmic units, which are called foot, one of the most common ones is the lamb, which is composed of an unstressed syllable and one stressed or accent syllable. Additionally, iambs can be included in different numbers which leads to a different rhythm in the poem this includes the iambic dimeter that is about creating verses by including two iambs, the iambic trimeter which is included three iambs and the iambic pentameter that means five iambs or ten syllables in which each pair is composed by one unstressed and one stressed syllable. Therefore, the description that matches the poetic form of iambic pentameter is "ten syllables divided into pairs of unstressed and stressed syllables".