I have done my graduation in ECE with 60.45%. Which course should I take up now amongst php, SQL, python, C, etc.?

It totally depends on your interests. Most popular and widely used languages are C and Python and they are getting their momentum back in the market. SQL is an easy language which can be learned easily and PHP is for server-side scripting for web development.

You can take up any course out of the mentioned courses Entirely depends on the course that you love the most and are most passionate about and analyze the future work conditions, scope and growth prospects before opting for it.