A measure of thermal energy transferred between two different bodies at different temperatures would be the correct answer. So, the third option.
Answer : The retention time is, 20 min
Explanation :
Retention time : It is defined as the amount of time a compound spends on the column after it has been injected.
Formula of retention time is:

Given:
Distance from injection point to center of peaks = 10 cm
Chart recorded speed = 0.5 cm/min
Now put all the given values in the above formula, we get:

Retention time = 20 min
Thus, the retention time is, 20 min
The pressure inside the flask on heating it is given as 1.21 atm.
<u>Explanation:</u>
As per Guy Lussac's law, the pressure of any concealed volume of gas particles will be directly proportional to the temperature of the container of the gas particles.
So P ∝ T
To convert celsius to kelvin, add 273.15 to the temperature value in celsius
Since, here the initial temperature of the flask is given as 24°C, so in kelvin it will be 297.15 K. Similarly, the final temperature is said to be 104°C which will be equal to 377.15 K. Then the final pressure will be increased as there is increase in temperature. So, the final pressure inside the flask can be obtained as


So, the pressure inside the flask on heating it is given as 1.21 atm.