Those are Direct Loan, FFEL Program loan, and Perkins Loan borrowers.
Have you received a Perkins loan?
Yes, I have.
Then you can also be eligible for a deferment while you are working to fully pay your Perkins Loan.
What can I do if I apply for an income-driven repayment plan?
Completing the application allows you to select an income-driven repayment plan by name or  request that your loan servicer determine what plan you qualify for. The loan servicer would then place you on the plan with the lowest monthly payment.
I would like more information about Parent PLUS borrower deferments, how do I qualify for this?
parents who received a Direct PLUS Loan to help pay their child's education and whose child is enrolled at least half-time at an eligible college or career school, may qualify for this deferment.
I see what you mean. Another request for a forbearance question. And how do I go about requesting such a reprieve?
Most types of forbearance are not automatic you need to submit a request to your student loan servicer, often using a form. For some types of forbearance, you must provide your student loan servicer with documentation to show that you meet the eligibility requirements for the forbearance you are requesting.
Also, for Parent PLUS borrower deferment. If I quit paying my student loan, what will happen to my requested deferment?
if you stop paying your loan before you've been notified that your request for deferment has been granted then your deferment will not be approved and your loan will become delinquent and you may go into default.
and what if I'm eligible for the deferment and rolled for at least half-time?
In most cases, your loan will automatically be placed into a deferment based on enrollment information reported by your school.
How will I know if my deferment is granted?