A.arr[arr.length]=x B.arr.length+arr=x C.arr+[arr.length]=x D.Array.pop(arr,x)
A.["eggs","milk","cookies"] B.["eggs","bread"] C.["eggs","milk","bread","cookies"] D.["milk","bread"]
A.全不正確 B.varc=a.push()+b.push() C.varc=a.concat(b) D.varc=a.join(b)