Which of the following can be a variable? Select all that are correct (Hint: Three are correct)
a. F
b. X
c. 3
d. a

A and B and D are correct because variables has letters not numbers

The only one that can’t be a variable is 3 because variables are letters you solve for to get numbers!

Hope I was helpful!

What does the start look like

Ohm's law tells you that i = v/r where v is equivalent voltage and r is equivalent resistance of the circuit
since all circuits have the same voltage, your question is really asking which circuit has the lowest total resistance, since the lower the resistance, the higher the current
circuit a has a resistance of 5 ohms; circuit c is in series so has a resistance of 10 ohms; circuit b is in parallel and therefore has a resistance of 2.5 ohms (review your notes on adding resistances in parallel and series); therefore b has the highest current