The president may decide to resume duties after an illness by informing congress that no inability exists,
but that decision can be challenged by
a. congress.
b. the vice president.
c. the vice president and a majority of the cabinet.
d. any representative in the house of representatives.

The correct answer is letter A.

The condition on the illness of a president can be challenged by the national congress, this because it is his duty to supervise the conditions of a president to govern.

In addition, it is the exclusive competence of Congress, among other duties: to resolve on international treaties and agreements that incur expenses to national patrimony; authorize the President of the Republic to declare war and to celebrate peace; approve or suspend the state of defense, federal intervention and state of siege; judge annually the accounts provided by the President of the Republic and evaluate the reports on the execution of the government plans; supervise and control the acts of the Executive Branch; analyze the concessions of radio and TV stations; plebiscites.