[Grammar] By car bombs versus with car bombs

[Flogger]

Hello.

I'm really confused about the usage of "by" and "with". Where should I use these prepositions? For instance, which of the following sentences is grammatical?

A) Terrorists attacked London by car bombs.

B) Terrorists attacked London with car bombs.

Thank you in advance.

 

[Tarheel]

Use the second one (B). Terrorists attacked London with car bombs. In other words, they used car bombs to attack London.