A 24-year-old woman who breast-feeds her infant develops a warm, painful mass and erythema of the overlying skin in the upper outer quadrant of the right breast. The pain and redness resolve with antibiotic therapy. Several months later, the same area is firm and the overlying skin is dimpled. Which of the following is the most likely cause of these findings?
a. Breast abscess with scarring
c. Fibrocystic change
d. Infiltrating mammary carcinoma
e. Traumatic fat necrosis