Because they have to be read in more than one sitting, which break me up the effect. I think
Focus on what you’re reading !
The correct answer should beThrough primrose-tufts, in that sweet bower,The periwinkle trail’d its wreathes;
Alliteration is when words in the same sentence begin with the same consonant and here we have "through, tufts, the, that, trail'd" as well as "primrose, periwinkle".
When Angelou describes her memory of her first visit to Mrs. Flower's home as "sweet-milk fresh," what she is suggesting about this remembered event is that A. the important event changed her life for the better.