WeeBee Company has three assembly labor classifications: S-1, S-2, and S-3. The three classifications are paid S16, $19, and $22 per hour, respectively. The assembly activity for a product uses an S2 employee who performs that task in 24 minutes. To reduce the activity cost per unit, a product engineer proposes using a higher-rated employee who can perform the assembly in 21 minutes. A manager proposes using a lower-rated employee who can perform the assembly in 30 minutes. Which of the following provides the most cost-effective solution? use the S1 employee use the S3 employee use either the S1 or S3 employee use the S-2 employee