Final answer:
In 2012, Cuba dropped the requirement for the travel exit permit, which allowed its citizens to travel abroad without government authorization. This was a part of larger economic and societal reforms under Raúl Castro's presidency. The measure is not related to the four types of visas listed but rather a type of internal government travel restriction.
Step-by-step explanation:
In 2012, Cuba announced it was dropping the requirement for a travel exit permit, which allowed Cubans to travel abroad without the previously required government authorization. This reform was part of a series of liberalization measures under the presidency of Raúl Castro. Although the question suggests visa types including tourist, work, student, and diplomatic visas, the specific change relates to the travel exit permit—a kind of control that fell under the category of internal government travel restrictions rather than the mentioned visa types.
The relaxation of travel restrictions was one of many changes that aimed to modernize Cuba's economy and society and came alongside other reforms like permitting Cubans to own cell phones and computers. However, internet access continued to be heavily regulated by the Cuban government. Because of the easing of restrictions, there was an increased flow of goods and remittances from Cuban family members residing abroad, particularly those living in the United States. This change also interacted with broader travel policies between Cuba and the U.S., including the 'wet foot/dry foot' policy, which played a significant part in the Cuban-American immigration experience.