A body has its centre of mass at the origin. The y coordinates of the particles of the body may be 1) all positive 2) all negative 3) all non-zero 4) positive for some cases and negative in other cases. Which of the following is correct ?

Question

\[\begin {array} {1 1} (a)\;1\; and\; 2 \\ (b)\;2\;and\;3 \\ (c)\;2\;and\;4 \\ (d)\;3\;and \;4 \end {array}\]