We are asked to find the number of elements in the set formed by the letters of the word "POSSESSIVENESS". The key point is that in a set, repeated elements are counted only once. Let's first list the distinct letters in "POSSESSIVENESS": The word "POSSESSIVENESS" consists of the following letters: \[ P, O, S, S, E, S, S, I, V, E, N, E, S, S \] The distinct letters are: \[ P, O, S, E, I, V, N \] Thus, the set formed by the distinct letters is: \[ A = \{P, O, S, E, I, V, N\} \] Therefore, the number of elements in the set is \(7\).
The correct answer is option (A): \(7\)