Since this is a school question, rather than providing you a straight up answer,  You may have some very good clues instead.

You did not mention a specific code or specification to obey, so I am going to go with AWS D1.1   Which you should have available in your class library.

See Clauses 5.3.2.1 and the associated commentary  C-5.3.2.1       These will give you some of the references and rules for electrode handling for low hydrogen SMAW.

The 90K electrode is rather uncommon for D1.1 but is covered in Group IV base metals in table 3.1 and matching electrodes in Table 3.2

You will also find good information for electrode storage and handling in  AWS A5.5/A5.5M, Specification for Low-Alloy Steel
Electrodes for Shielded Metal Arc Welding.   Your school should also have a copy of this.

The data sheets from any SMAW electrode supplier will also offer some guidance in this regard.