Which of the following statement is NOT true ?

Question

$\begin{array}{1 1} \text{(a) Magnesium has a stronger desire to lose electrons than does mercury } \\ \text{(b) Gold is often naturally found in its elemental state } \\ \text{(c) iron will not replace zinc in a single replacement reaction } \\ \text{(d) Calcium is often naturally found in its elemental state } \end{array}$