The z-transform of x[n]= {1,0,-1,0,1,-1} (1st 1 as the reference variable) is __________

• A. 1+2z-2 -4 z-4 + 5z-5
• B. 1-z-2 + z-4 – z-5
• C. 1-2z2 + 4z4 – 5z5
• D. 1-z2 + z4 – z5
• E. is __________a) 1+2z-2 -4 z-4 + 5z-5b) 1-z-2 + z-4 – z-5c) 1-2z2 + 4z4 – 5z5d) 1-z2 + z4 – z5