All of the following chemical reactions are double replacement reactions EXCEPT

AMg(OH2)2 + 2HCI → MgCl2 + 2H2O

BPb(NO3)2 + 2KI → 2KNO3 + PbL2

CCH4 + 2O2 → CO2 + 2H2O

DHCI + NaOH → NaCl + H2O

Can never get this one figured out. :(