i) Yes, this type of time-temperature graph is possible.
As time increases, temperature also increases.
ii) Yes, this type of time-temperature graph is possible.
As time increases, temperature decreases.
iii) No, this type of time-temperature graph is not possible.
Here, time is constant, which is not possible and temperature increases,
iv) Yes, this type of time-temperature graph is possible.
As time increases, temperature is constant..