The correct answer is Option 2: 2 only.

Explanation:

1. Belle 2 experiment:

Belle 2 experiment is a particle physics experiment conducted at the KEK High Energy Accelerator Research Organization in Japan. It is designed to study the properties of B mesons, which are subatomic particles that contain a bottom quark. This experiment is not related to Artificial Intelligence, so Option 1 is incorrect, which includes 1 as a correct match.

2. Blockchain technology:

Blockchain technology is a digital ledger technology that underlies cryptocurrencies such as Bitcoin, Ethereum, and others. It is a decentralized, distributed ledger that records transactions across a network of computers, making it secure and tamper-proof. It is widely used in the financial industry and has potential applications in other areas as well, such as supply chain management, healthcare, and voting systems. Option 2 is correct as it correctly matches blockchain technology with digital cryptocurrency.

3. CRISPR-Cas9:

CRISPR-Cas9 is a gene-editing technology that allows scientists to edit genes with a high degree of precision. It works by using a small RNA molecule to guide an enzyme, called Cas9, to a specific location in the genome, where it can make a cut and modify the DNA. This technology has potential applications in medicine, agriculture, and other fields. However, it is not related to particle physics, so Option 1 is incorrect, which includes 3 as a correct match.

In conclusion, the correct match is Option 2: 2 only, which matches blockchain technology with digital cryptocurrency.