It is this first choice. You might have been tempted here if you got a little bit confused, hey maybe the fourth minute is after we've crossed that t is equal to four, but no, that would be the fifth minute. This would tell us, this would tell us our change over the first four minutes, not just during the fourth minute. And then this, well this is just gonna be zero. If you're taking, what is the change in the value from three to three? Well it didn't change at all in that, because it's essentially at an instant. There's no time that passes from three to three.