Iambic pentameter is a metric lyne used in English poetry, which stressed and unstressed syllables, alternating one another. So, it's a kind of rhythm like heartbeats.
So, using iambic pentameter you need to firstly put I unstressed syllable followed by a stressed one, doing this five times in a sentence you reach the pentameter characteristic.
Answer: A: “You call yourself poor, my friend; you never were so rich,—you never knew the boundaries treasures of excellence you possessed in that woman.”
