Detailed Instructions: In this task, you're given a passage, further information available on a particular linked term from the statement, and a question. Your job is to generate the answer to the question by using the information provided. If there is no clear answer obtainable, output 'none'.
Q: Passage: Kazusa was originally part of a larger territory known as , which was divided into "upper" and “lower” portions (i.e. Kazusa and Shimōsa) during the reign of Emperor Kōtoku (645–654). It was well-known to the Imperial Court in Nara -period Japan for its fertile lands, and is mentioned in Nara period records as having supplied hemp to the Court. Kazusa was divided into 15 counties, of which the four counties comprising the district of Awa were separated in 718 into a separate province. The exact location of the capital of Kazusa is not precisely known, but is believed to have been somewhere within the borders of the modern city of Ichihara, Chiba. The ruins of the kokubun-ji, or provincial temple, of Kazusa has been located in the Sōza district of Ichihara. The kokubun-ji was first excavated in 1949, and is on a plateau above the Yōrō River in close proximity to Tokyo Bay. The site is protected as a Designated Historic Site of Japan. However, the Ichinomiya of Kazusa Province is the Tamasaki Shrine in what is now the town of Ichinomiya, Chiba, on the opposite coast of the province.
 Link Information: The is a river in Chiba Prefecture, Japan. It is 73.4 km in length Question: How long is the Yoro river?
A:
Answer: 73.4 km