The answer is C because of the ionization energy trend
Your pattern of breathing increases, making it faster than usual, when you're exercising because you're pushing your body to work harder and speeding up your heart rate making you tired.
When you're resting your breathing pattern should be steady and normal since you aren't doing anything that requires lots of body work or something that would make you out of breath.
Hope this helps,
Davinia.
The correct answer is Bromine
Hope this helped:)
A tend line I believe (I am going off the other guy cause they are right.)