Final answer:
After descending 253.7 feet and ascending 216.3 feet, the scientist is 37.4 feet below sea level. It would take her approximately 11 seconds to reach the surface at a speed of 3.4 feet per second. However, the calculated value does not match any of the answer choices given, indicating a possible error in the calculations or the question details.
Step-by-step explanation:
To calculate the time it will take for the scientist to return to sea level at a speed of 3.4 feet per second, we first need to determine the total distance she has traveled downward and then ascended.
The scientist descends at 4.3 feet per second for 59 seconds, which is 4.3 feet/second * 59 seconds = 253.7 feet underwater.
She then ascends at a speed of 2.1 feet per second for 103 seconds, which is 2.1 feet/second * 103 seconds = 216.3 feet upwards.
The total descent minus the ascent provides us with the net depth: 253.7 feet - 216.3 feet = 37.4 feet below sea level.
To find out how long it takes to ascend at 3.4 feet per second to reach sea level, we divide the net depth by the ascent speed: 37.4 feet / 3.4 feet/second = 11 seconds.
However, this value is not among the options provided, which seems to suggest there might have been either a calculation error or a misunderstanding in the way the question was posed. As precision is key in providing correct information, further review or additional information from the student would be required to provide an accurate answer to the question.