blazer wont start

My friend has a 92 or 94 blazer.
It won't start when its raining.
When it's try it has dificulty starting.
We live in Michigan and for the past week I thuink the cold and semi wet weather has been an issue too.

I'm haven't gotten a good look at the truck but I have a few ideas what could be thr problem.

a)A wire form the dash to starte solenoid under the hood shorting out when wet.

b)The Starter solenoid is going bad.

c)The Starter is bad.

d)Need a new battery.

I'm pretty sure all of her accessories are running(I asked her but she couldn't remember).

So does anyone have any idea what it could be?

When was the last time a tune up was done?

Plugs, wires, cap and rotor. Not to mention fuel and air filters.

Does it crank and not fire? Or no crank?

If it cranks and not fire, look at your ignition like coil, coil wire, distributer cap and rotor.

If it won't crank, you have to trace the crank circuit. Start at the ignition switch to see if you have power at the yellow wire with the key in the crank position. It then goes to the neutral safety switch where the wire in is yellow and wire out is purple. Then it goes to the starter.