Final answer:
The subject of this question is Geography. The question is asking whether there is a rapid transit tunnel under the East River at a specific street.
Step-by-step explanation:
The subject of this question is Geography. The East River is a waterway in New York City, separating Manhattan from Brooklyn and Queens. The question is asking whether there is a rapid transit tunnel under the East River at a specific street. This is a geographic inquiry about transportation infrastructure in the area.
For example, one well-known rapid transit tunnel under the East River is the 4/5/6 Subway Tunnel, connecting Manhattan and Brooklyn. However, it is important to note that the question does not specify a particular street, so a definitive answer cannot be given without further information.