设所有被4除余数为k(k=0,1,2,3)的整数组成的集合为Ak,即Ak={x|x=4n+k,n∈Z},则下列结论中错误的是()
A.2016∈A0
B.-1∈A3
C.a∈Ak,b∈Ak,则a-b∈A0
D.a+b∈A3,则a∈A1,b∈A2