Which one of the following statements are always true for neutral atoms

Question

$\begin{array}{1 1}(a)\;Atomic\; number\; is\; equal\;to\; number\; of\; electrons\\(b)\;Mass\; number\; is\; equal\; to\; sum\; of \;electrons\; number\; and\; neutron\; number\\(c)\;Atomic\; number\; is\; equal\; to\; neutron\; number\\(d)\;Both\; I\; and\; II\end{array}$