16/18, which is 8/9 reduced
You can compare the angles or other measurements to find the one you are looking for.
Answer:
Option C.
Step-by-step explanation:
By definition, a function f(x) is even if 
We know by definition that the function sin(x) is odd and the function cos(x) is even.
With this information we can analyze each function and find out which is even.
A. The first function is not even because 5sin(x) is an odd function.
B. The second function is not even because 2tan(x) is not an even function.
C. The third function is even, because -cos(x) and
are even functions.

D. The fourth function is not even because csc(x) is not an even function.
Therefore the correct answer is the option C. 
Tow ratios that have the same value when simplified.
Hope this helps!!;)