[单选题]
Capacitances of 10 mF and 20 mF are connected in pa :2 m7iqyntd d;f3tqi3rallel, and this pair is theo0+ *bihv*jf anavi+b jf*o 0*h connected in series with a 30-mF capacitor. What is the equivalent capacitance of this arrangement?
A. $10 \; mF$
B. $15 \; mF$
C. $25 \; mF$
D. $60 \; mF$
