How Much Charge Can Be Placed on a Capacitor of Plate

How much charge can be placed on a capacitor of plate area 20 cm² with air between the plates before it reaches "atmospheric breakdown" where E = 3.0 *10⁶ V/m? ( $\varepsilon$ ₀ = 8.85 *10^-12 C²/N.m²)

A) 6.6 *10^-7 C
B) 2.7 * 10^-8 C
C) 5.3 *10 ^{- 8} C
D) 4.0 *10 ^{- 7} C