This checks a basic fact of Mughal history, the age of Akbar when he became emperor.
Eleven Years: this underestimates Akbar's age at accession by about two years.
Twelve Years: this is also below the actual recorded age.
Thirteen Years: correct. After Humayun's sudden death in 1556, Akbar was crowned emperor at around thirteen years old, and the task of consolidating and expanding the Mughal Kingdom initially fell on him under the regency of Bairam Khan.
Fourteen Years: this overstates his age by about a year.
The correct option is C, thirteen years, Akbar's age at his accession to the Mughal throne in 1556.