#### Answer

We can put two capacitors in parallel, and then we can put another capacitor in series with these two capacitors.

#### Work Step by Step

We can find the equivalent capacitance when we put two capacitors in parallel:
$9.0~pF+9.0~pF = 18.0~pF$
We can find the equivalent capacitance when we put another capacitor in series with these two capacitors:
$\frac{1}{C_{eq}} = \frac{1}{18.0~pF}+\frac{1}{9.0~pF}$
$\frac{1}{C_{eq}} = \frac{3}{18.0~pF}$
$C_{eq} = 6.0~pF$
We can put two capacitors in parallel, and then we can put another capacitor in series with these two capacitors.