If x = a b , y =b c , z = c a , then(1 x)(1 y)(1 z)is equal to a + bb + cc + a(1 + x)(1 + y)(1 + z)

• A. 1
• B. 0
• C. 2
• D. <table><tr><td style="border-bottom:1px solid #000000;vertical-align:bottom;padding-bottom:2px;"><center>1</center></td></tr><tr><td style="text-align: center;">2</td></tr></table>