Personal data may be processed only if:
(a) processing is necessary for the performance of a task carried out in the public interest on the basis of the Treaties establishing the European Communities or other legal instruments adopted on the basis thereof or in the legitimate exercise of official authority vested in the Community institution or body or in a third party to whom the data are disclosed, or
(b) processing is necessary for compliance with a legal obligation to which the controller is subject, or
(c) processing is necessary for the performance of a contract to which the data subject is party or in order to take steps at the request of the data subject prior to entering into a contract, or
(d) the data subject has unambiguously given his or her consent, or
(e) processing is necessary in order to protect the vital interests of the data subject.