Which of the following species is paramagnetic

According to the options –
a) A carbanion has a negative charge on the carbon, which means one pair of electrons is not bonded and the other six electrons are bonded to other atoms. So, it contains eight electrons. It is diamagnetic.
b) A carbonium ion has a positive charge on the carbon and it has 4 electrons. It is also diamagnetic.
c) Free Radical contains any molecule of a species capable of independent existence that contains an unpaired electron in an atomic orbital. Therefore, it is paramagnetic in nature.