Which one of these is a function?

a coordinate grid containing a u shaped graph with arrows on its ends. the u shape opens upwards and the bottom of the u shape is located at the origin.

coordinate grid with graph of a vertical line at x equals 3.

a coordinate grid containing a u shape with arrows on both ends that opens to the right. the bottom portion of the u passes through the origin.

a coordinate grid with the graph of a circle centered at the origin and passing through the point begin ordered pair 2 comma 1 end ordered pair.

I hate saying I believe, but I am not totally sure with this one. At least its better than you getting no answer. Anyway, ugh I hate saying "I believe" its so un-reassuring. I believe the answer is the third one.

Step-by-step explanation:

It can't be the second one, cause that doesn't matter.

It cant be the last one. A circle can't be a function because if you do the vertical line test, you will find to points on the vertical line instead of one.

It can't be the first one because that would also fail the line test. If it opens upwards, than that would mean that there are multiple points on the vertical line test.

--Your best answer is the third one--

(If you need a second-best answer, it will be the first one, cause that is the one that makes the second-best sense)

PLEASE MARK BRAINLIEST! I WOULD REALLY APPRECIATE IT IF YOU DID. I JUST WANT ONE MORE BRAINLIEST...

I just took the test,

Step-by-step explanation:

The answer is the u that points upwards, i don't know why but thats the correct one

80%

step-by-step explanation:

c.

step-by-step explanation:

she should of added 9^2 and 12^2. that is because it is a^2+b^2=c^2. c^2 is the hypotenuse and should always be bigger than the other two numbers. which is why she should of added 9 squared and 12 squared together instead of 15 squared.