Is this english sentece a statement or not and why?

**Consider:**

a)x=2

b)All politicians are honest

c)there exists a real number x such that x^2=x

Can someone please help me determine a way to figure out whether something is a statement? I am correct most of the time, but when my prof. tries to trick he is successful lol. What should I look out for? Can you provide an example of a tricky sentence and then show me how u figured out whether it is a statement or not?

**My attempt:**

a)IS NOT a statement b/c we do not have proof that it is true for all 'x', Therefore, it can be true for this case, but x can always be a different number.

b)I would say b is a statement. B/c it sounds like it is saying the sentence is true, but how we do we know its true? if it wasn't proven it can be either true or false and a statement that is true or false is NOT a statement, can someone explain?

c)This is a statement as long as I find 1 case where this is correct right?