To find Tina's gross annual income, we consider her earnings from her job as a lifeguard. She will earn a total of $3000 for the whole summer.
Since the question asks for her gross annual income, we do not need to consider deductions or other income sources (since she plans not to have any).
The total amount she earns over the summer is $3000, and since there are no other jobs or income mentioned, this is her gross annual income for this specific job.
Therefore, the answer is:
C) $3000