Answer:
C. Complete subject.
Step-by-step explanation:
A complete subject consists of the simple subject and all words related to it. In the sentence above, the simple subject would be only the word Melinda; however, since the appositive phrase undaunted by these brushes with death is also included in the subject, then it is a complete subject.
A compound subject consists of at least two words joined by the conjunction and (e.g. Melinda and John) which isn't the case here.