The metal sheet shown in figure, with two holes cut of unequal diameters $a_{1}$ and $d_{2}\left(d_{1}>d_{2}\right)$. If the sheet is heated:
(a) both $d_{1}$ and $d_{2}$ will decrease
(b) both $d_{1}$ and $d_{2}$ will increase
(c) $d_{1}$ will increase, $d_{2}$ will decrease
(d) $d_{1}$ will decrease, $d_{2}$ will increase