Yash,it is not really possible for us to tell the exact number of candidates who appeared for PESSAT 2019. But we can tell you at least 15k people have appeared.

Depending on your rank, you might have a chance of getting EE branch.

Other than that, you can definitely get all the other branches which includes Civil, Mechanical, BioTech etc. But it depends on the number of students who appeared for the exam and as well as the difficulty of the paper.

Feel free to ask if you have any more queries.

Hope this helps!

All the best!