Which of the following definitions are correct?

a. bulla: an elevated, circumscribed lesion filled with turbid fluid (pus)
b. nodule: solid, elevated, hard or soft, larger than 1 cm
c. petechiae: tiny punctate hemorrhages, 1 to 3 mm, round and discrete, dark red, purple, or brown in color
d. papule: a hypertrophic scar
e. vesicle: also known as a friction blister

All of them except the papule.

Explanation:

The other options define correctly the damage in skin, they have they differences among them but they are quite well defined.

In the case of the papule, is well defined it borders, it has a solid content and the size is less than 1 cm in average.

Is cause by an excess of oil in skin, this oil clog the pores of the skin and makes a small bag that looks red and bump.