Recently in news, Wedelstein 7X is related to

Wendelstein 7-X (W7-X) is a fusion research device at the Max Planck Institute for Plasma Physics in Greifswald, Germany. It is a stellarator, which uses twisted superconducting magnetic coils to confine superheated plasma long enough for fusion reactions. Fusion is a nuclear energy process, so option D is correct.

Why the others fail:

• Steam energy: Steam is a working fluid in conventional power plants. It is not the name of a research experiment like W7-X.
• Solar energy: Sunlight is harnessed through photovoltaic or solar thermal systems. Fusion powers the Sun, but W7-X does not use solar radiation.
• Thermal energy: This is a broad category, and fusion does release heat. But the question asks about the specific technology, which is nuclear.

Concept: the core idea is nuclear fusion versus fission. Fusion is attractive for clean baseload power, and the ITER project in France, in which India is a partner, is the main global effort. For Mains, link it to energy security and climate-change mitigation in GS III. W7-X has set several plasma-duration records in recent years, so keep that in mind as a current-affairs point.

Trap: Aspirants see that the Sun runs on fusion and pick Solar Energy. Remember that the question names a specific fusion device, not a solar technology.