Question

1. if you are attached to your cell phone at work, your employer might wonder if you care about your job or if youre ........... on the phone using apps texting paying attention

Explanation:

The sentence implies that being overly attached to the cell phone at work makes the employer question the employee's focus on the job. "Paying attention" directly relates to being focused on work, which is the concern here. "On the phone", "using apps", and "texting" are more about actions on the phone rather than the overall concept of being focused (or not) on the job as the employer would wonder.

Answer:

paying attention