In the following question out of the four options only one is correct, write the correct answer.
Linear equation in one variable has:
(a) only one variable with any power.
(b) only one term with a variable.
(c) only one variable with power 1.
(d) only constant term.
Fill in the blanks to make each statement true:
In a linear equation, the ................ power of the variable appearing in the equation is one.