The correct answer is A. Iambic tetrameter
Step-by-step explanation:
In poetry the structure of verses or how verses are composed is called meter, the structure of verses or meter relies on the number of feet, a foot is a combination of stressed or accented syllable and one or more syllables that are not stressed. In the case of the line of verse form a poem of Emily Dickinson there are four feet and each of the feets that are separated from each other with slash (/); these feet are composed by a stressed syllable and only one that is not stressed, this type of combination is called "iambic", also, as there are four feet that are iambic, this verse is an example of "Iambic tetrameter" as iambic means the combination of a stress and an unstressed syllable and tetrameter means four and this verse is composed of four combinations of stressed and unstressed syllables or iambic tetramenter.