Which peice of text evidence best supports the inference that thames helped the london flourish

There is no background text in the question. I would therefore attempt to say how the river Thames has helped the city of London to develop and flourish.  

Explanation:

The Thames River is a historic 215-miles long river that currently flows through the city of London in the United Kingdom.

It is historic because it was first discovered about 2000 years by the Romans who were the earliest settlers in London after the war.

Identifying it as a strategic trading route, the Romans built a city around it calling it Londinium and started using it as a gateway for merchandising their goods. The Romans also constructed the first bridge over the river. Till date, over 200 bridges have been constructed over the Thames.

The trade route via the Thames river rapid economic and infrastructural development to the city of London.

It is also a source of the drinking water for the residents of the city after a major sewage system was constructed to combat the stench that emerged from the dumping of refuse and sewage into the river by the early settlers.

Finally, the Thames is a very important a tourist destination in the city of London attracting millions of tourists who come to see it and the iconic London Bridge that is currently standing over it  

it is an infinitive phrase with a subject.