In lamellipodia, actin polymerization is nucleated by ...(1), while depolymerization is catalyzed by ...(2).

A) (1) formin; (2) gelsolin
B) (1) Arp 2/3 complex; (2) gelsolin
C) (1) formin; (2) cofilin
D) (1) Arp 2/3 complex; (2) cofilin
E) (1) formin; (2) capping protein