Yes a candidate could take more than 1 job offer. However once s/he has joined a company, s/he shall be placed under moratorium and will not be considered for future job openings through eLitmus.
If the candidate leaves the job that he/she got via eLitmus, s/he may request for moratorium to be lifted. This can be done by presenting the original relieving letter from the company at eLitmus office in Bangalore OR the eLitmus needs to receive a mail from the company intimating that the candidate has resigned. The mail received from the company id will be forwarded to the eLitmus SPOC in the company for approval.