Question $3$

Select which inputs are valid for the expression rule.

nil

$(10)$

$,$

$5.$toString$()$

$1$:$2\mathrm{.}3$

$x+10(x\%y)\%z1$

$x+10$

$(x\%y)\%z$

$"x"\frac{?}{?}21$

$1$

$x+10$

$(x\%y)\%z$

$"x"\frac{?}{?}2$