Which one is not related to transpiration?

Transpiration is lowest in which of the following conditions?

The transpiration in plants will be lowest when:

Given below are two statements:
Statement $I$: The forces generated by transpiration can lift a xylem-sized column of water over $130 \text{ meters}$ in height.
Statement $II$: Transpiration cools leaf surfaces,sometimes by $10$ to $15$ degrees,through evaporative cooling.
In the light of the above statements,choose the most appropriate answer from the options given below:

Concentration of $CO_2$ from nature which is able to induce closure of stomata is

Which one of the following would lead to stomatal closure?