Nan's salary in $2023$ is $$40,000.$ Nan elects to defer $5\%$ of her salary into her employer's

$401(k)$ plan. Her employer provides a matching contribution on the first $4\%$ contributed.

What is the net impact on Nan's $2023$ taxable income from these items?

a$.$ $$41,600$

b$.$ $$38,000$

c$.$ $$39,600$

d$.$ $$40,000$