If the filtration system does not work, how can someone use the document to solve the problem? by repeating the installation steps described in the document and referring to the diagram
by installing the filter in a different order than the one in the document
by referring to the diagram to come up with another way to install the filter
by installing the heater first to see if that allows the filter to function

A. by repeating the installation steps described in the document and referring to the diagram

The last sentence under "Keeping It Clean" says "If the filtration system does not start when plugged in, repeat the installation steps. If it still does not work, consult your aquarium store." This is pretty much what answer A says.

Here's a photo of Edge just incase, have a good one.

c.to compare several aspects of the tragedy to other worldwide tragedies

whether dad arrives in time for the game depends on his conference. subject