That is red spectrum........................
Answer with Explanation:
We are given that
Resistance,R=130 ohm
Potential difference, V=30 V
Capacitor,C=2.1pF=



a.Maximum flux



b.Maximum displacement current,
c.We have to find electric flux at t=0.5 ns






d.Displacement current at t=0.5ns


Potassium is the 19th element so it is B