Sales of marketable securities at par will result in inflow,outflow or No Flow of cash. In oswaal question bank the answer provided is inflow, but I think marketable secutities is a cash equivalent so selling it at par will result in no flow. Am I correct?

Yes Darshil, you are absolutely correct. Sale of marketable securities will have no impact on the cash flow statement, since it is a part of cash and cash equivalents. Whether you hold marketable securities or sell them and hold cash, it makes no difference to your cash position.