The correct answer is turbulent current.
C. low tide
D. turbulent current
The correct answer is (D) A turbulent current, such as a surface current flowing away from shore; a turbulent stretch of water caused by violent opposing currents. Also, the undertow caused by incoming waves.
Riptide comes from rip + tide.
Examples of use:
- The very strong riptide made for dangerous swimming that day.
- A riptide beyond the mouth of the lagoon presented an additional obstacle.