Hi aspirant,

ECM is an unique course where you are taught subjects that come under both CSE and ECE. It is a hot branch and should be your first choice.

Electronics and communication engineering is a core branch which utilizes nonlinear and active electrical components to design electronic circuits, devices, integrated circuits and their systems. It has great demands admist the rise of technology and machinery.

At last electrical and electronics engineering deals with the study of application of electricity, electronics and electromagnetism. It should be preferred at last because major a part of it is covered in ECE.

Hope it helps!!