Hello teachers with or for？

[Harry12345]

The speaker seemed to be looking for the words______he could express his concern about public safety.
A with which B for which

I don't which one I should choose with, or for? It's too difficult! please help me.

 

[Jenniferhu]

A.

For here implies that you help or make something happen, whereas with means that something helps or supports you to do things. Words are like tools, and they help you express your ideas. In most circumstances, you work with a tool, not for a tool.

 

[emsr2d2]

The speaker seemed to be looking for the words______he could express his concern about public safety.
A with which B for which

I don't which one I should choose with, or for? It's too difficult! please help me.

If you think about what would happen if the speaker was successful in finding those words, you get "He expressed his concerns about public safety ________ words". Which would you put there, "with" or "for"?