The table describing a proportional function is (partially) given below. What is the output ( $\displaystyle{y}\usepackage{cmbright}\Huge\$ -value) corresponding to the input $\displaystyle{x}={2}?\usepackage{cmbright}\Huge\$

$\displaystyle{x}\usepackage{cmbright}\Huge\$
$\displaystyle{y}\usepackage{cmbright}\Huge\$

1

2

3 15

$\displaystyle{x}\usepackage{cmbright}\Huge\$	$\displaystyle{y}\usepackage{cmbright}\Huge\$
1
2
3	15