What should be done if you discover that, certain newly recruited employees are inefficient and less qualified?

a) Noticing those employees to recovery their required qualifications immediately.

b) After fulfill their qualifications, arrangement for required training properly.

c) Held-up their incremental salary till recovery their required qualifications and skills. 

It depends on the Labor law in your country. There should be a probation period in which the employer can dismiss the employee anytime without any legal implications.New employees that are not performing well don't pass the probation period.