Answer:
See figure 1
Explanation:
In this question, we have to check the five-carbon ring. In this ring, we have a double bond between the nitrogen atoms a double bond between carbons 10 and 11. Finally, inside the ring, we have a pair of oxygen number 9. These are the electrons that are involved in the resonance. (See figure 1)
So, how many electrons we have?
Double bond N/N = 2 electrons
Double bond C/C = 2 electrons
Lone pair from oxygen= 2 electrons
In total, we will have 6 electrons. Lets apply the huckle rule:
4n+2=6
n=(6-2)/4
n=1
We obtain a whole number for this molecule, therefore the molecule complies with the huckel rule.
I hope it helps!