Which below is the most fitting example of signaling?

Options:

T$-$Mobile offers free iPhones with a $24-$month service contract and half$-$price iPhones with a $12-$month service contract to new customers.

Poisonous caterpillars have evolved to wear bright colors that make them stand out from the environment.

A high school senior includes her SAT score in applications to colleges that require SAT scores.

A millionaire offers a flat $1\%$ commission on gains and losses to a wealth management firm.

A company's labor contract offers one extra paid vacation day per year for each additional year an employee serves the company.

Amazon offers free shipping on orders larger than $$35($for non$-$Prime members$).$