What is the sex of this plant ??

Guessing you are using regular seed and trying to sex them early. The plants are not showing anything that can be distinguished between male or female. This will only happen if they are switched into flower of a 12/12 photoperiod. Doing this and switching them back to 18/6 can cause undue stress but its one way of figuring it out right away assuming the plants are mature. Another way of sexing them is by just waiting. The males will show sex earlier then the females in my experience. Once the plants are mature "week4-6+" they should some pre-sex traits. Like pistils in the nodes but not enter flower. This means they are ready to be flipped to flower if your done training them. I found this when googling your strains name from the diary. https://www.puresativa.com/tangieland-regular-cannabis-seeds-by-crockett-family-farms Is this the breeder? Best Of Luck!