Filling of returns

Here the word "employe" plays a major role. A professional who is working as an employyee is deemed to get salary from  the company and he is liable to file ITR1-  for SALARIED employees

Alternatively, if a professional is working in a company but he is not an "employee", he will received professional fees from the company, and he can file ITR4- for BUSINESS/PROFESSION, where he can emphasize on his profession.

can we use ITR-2A...also........

It is advisable that if you do not have any other income other than salary, you should use ITR-1. 

ITR 2A is applicable for those who have salary income and own more than one house property and DO NOT have any capital gains.