6/9 is in 2/3 all you do is multiply numerator and denominator by 3
The cotangent function is defined as the ratio between cosine and sine of a given angle, i.e.

Since you can't have zero at the denominator, the cotangent function is not defined when the sine is zero.
Let's look at your option:
, so the cotangent is defined here
, so the cotangent is not defined here
, so the cotangent is defined here
, so the cotangent is defined here
Answer:
0
Step-by-step explanation:
The only two numbers that would make the whole expression divisible by 8 are 0 and 8. Since the number also has to be divisible by 5, though, the last digit must be a 0 or a 5. Therefore, A=0. Hope this helps!