What will be assigned to the string variable pattern$\_$fter the following code executes?

$i=3$

pattern $={?}^{\text{'}}\text{'}{?}^{\text{'}}**(5**i)$

Nothing; this code is invalid.

${?}^{\text{'}}z**{15}^{\text{'}}$

$\text{'}$zzzzzzzzzzzzzzz$\text{'}$

$\text{'}$zzzzz$\text{'}$