$[1]$ You scheduled seven conference calls for this morning between $10$ and $11$ a$.$m$.[2]$ Generally, the company limits the number of conference calls to three per hour. $[3]$ I$\text{'}$m letting you know that in the future, we should be more careful about scheduling.

Which revision limits the long lead$-$in in sentence $3?$

In the future, we should be more careful about scheduling.

I$\text{'}$m letting you know so that in the future we are more careful about scheduling calls.

So that you know in the future, we should be more careful about scheduling.