Contrapose the following propositions and state whether the contrapositive is logically equivalent or not logically equivalent to the given proposition.

a. All physicians whose licenses have been revoked are physicians ineligible to practice.

b. No unpersecuted migrants are migrants granted asylum.

c. Some politicians who do not defend Social Security are politicans who do not want to increase taxes.

d. Some opponents of gay marriage are not opponents of civil unions.

Perform the operations of conversion, obversion, and contraposition as indicated.