What transition would best connect these ideas? many americans thought trains too dangerous, even banning them from use. americans were building more railroad miles than canals in the 1830s. a.)however b.)undeniably c.)for example d.)as a result

The answer is: However.

Explanation:

However means, despite something so basically it is saying that although americans thought trains were too dangerous, they were still building more railroads, something contradictory. As a result is not possible unless it wasn't contradictory, for insatance: As a result, americans are not building anymore railroads. For example gives you the prompt to give an example of your argument. And undeniably means to be indisputably, no one can say the opposite.

the answer is five curious-looking beans