What was the purpose for the Native Americans to lay claim and invade Alcatraz?

According to the term of the Treaty of Laramie, the United States government had agreed to give possession of any federal lands that are abandoned, unused, or retired must be given to the Indians who once were the occupants. So, when this term of the agreement wasn't followed through by the government, the Indians 'forcefully' invaded and occupied the Alcatraz island as a form of protest, to get back their lands as promised by the government and also to make their stand clear about the issue.

Explanation:

The United States had previously promised the Native Indians a right to get their lands back or in some cases, be given the right to occupy any federal lands taken from them that are left unoccupied. This right was a term in the Treaty of Fort Laramie between the US government and the Lakota tribe.

But when the US government did not keep its promise of the treaty, the Indians unitedly began to plan to overtake federal lands. One instance is the Occupation of Alcatraz in 1969-71 during which a group of Indians invaded and occupied Alcatraz Island. Their main purpose for this 'illegal or forceful' occupation was to make their point clear, to repossess the lands as promised by the government, and also to remind the government of its promise and if not followed, they (Indians) have the right to follow through the agreed terms.

the correct answer is (a) . answer should be simple, clear and brief.