## **Core Concept**
The discovery of radioactivity is attributed to Henri Becquerel, a French physicist. Radioactivity is a phenomenon where unstable atomic nuclei lose energy through radiation. This concept is fundamental to nuclear physics and has applications in various fields, including medicine, energy production, and scientific research.

## **Why the Correct Answer is Right**
Henri Becquerel discovered radioactivity in 1896 when he found that uranium salts emitted a form of radiation that could penetrate solid objects and cause photographic plates to become exposed, even in the absence of light. This discovery was a pivotal moment in the history of physics, marking the beginning of nuclear physics and leading to further research by Marie Curie and others.

## **Why Each Wrong Option is Incorrect**
- **Option A:** 1895 - This is incorrect because while 1895 is close to the actual year of the discovery, it predates Becquerel's actual finding.
- **Option B:** 1897 - This is incorrect because, although 1897 is the year when J.J. Thomson discovered the electron, it is not the year Becquerel discovered radioactivity.
- **Option D:** 1898 - This is incorrect because, while 1898 is notable for other scientific discoveries, it is not the year Becquerel discovered radioactivity.

## **Clinical Pearl / High-Yield Fact**
A key point to remember is that Henri Becquerel's discovery of radioactivity was accidental. He had been studying phosphorescence in uranium salts and left a sample near an unexposed photographic plate, which was then found to be exposed. This serendipitous discovery highlights the importance of curiosity and meticulous scientific observation.

## **Correct Answer:** C. 1896.