The answer is the option C, which is: C.) [tex] 9 [/tex] is an element of [tex] T [/tex].
The explanation of this answer is shown below:
In mathematics, the symbol ∈, which shown in the problem above, is used to express that an element belongs to a set.
As you can see above, the element 9 belongs to the set [tex] T [/tex], therefore, [tex] 9 [/tex] is an element of [tex] T [/tex], or: [tex] 9 [/tex]∈[tex] T [/tex].