Tapti River flows through a rift valley.

Explanation:
A rift valley is a lowland region that forms when the Earth's crust is stretched or pulled apart, creating a linear-shaped depression. This process is known as rifting. Rift valleys are often formed along tectonic plate boundaries, where the Earth's lithosphere is being pulled apart, leading to the formation of a rift zone.

The Tapti River is a major river in central India. It originates in the Satpura Range in Madhya Pradesh and flows westward through the states of Maharashtra and Gujarat before finally emptying into the Arabian Sea. The Tapti River flows through a rift valley known as the Narmada-Tapti rift zone.

The Narmada-Tapti rift zone is a geological formation that extends for about 1,100 kilometers from the Arabian Sea in the west to the Son River in the east. It is a result of the rifting of the Indian subcontinent from the supercontinent Gondwana during the Mesozoic era. The rift zone is characterized by a series of parallel faults and grabens, which are down-dropped blocks of land bounded by faults.

The Tapti River follows the course of the Narmada-Tapti rift zone, flowing through the grabens and valleys formed by the faulting process. The rift valley provides a natural pathway for the river to flow, as the land is lower and more easily eroded compared to the surrounding uplands.

In contrast, the other rivers mentioned in the options do not flow through a rift valley. The Ganga River, also known as the Ganges, is a transboundary river that flows through the Indian subcontinent and does not follow a rift valley. The Tungabhadra River is a tributary of the Krishna River and does not flow through a rift valley either. The Krishna River, another major river in India, flows through the Deccan Plateau but does not pass through a rift valley.

Therefore, the correct answer is option D - Tapti River. It flows through the Narmada-Tapti rift zone, which is a rift valley formed by the rifting of the Indian subcontinent.