A student solved 3x−4=x7 in six steps, as shown.

Step 1: 3=x(x−4)7
Step 2: 21=x(x−4)
Step 3: 21=x2−4x
Step 4: 0=x2−4x−21
Step 5: 0=(x−7)(x+3)
Step 6: x=−3, x=7
Which statement is an accurate interpretation of the student's work?

A The student solved the equation correctly.

B The student made an error in step 2.

C The student made an error in step 5.

D Only x=7 is a solution to the original equation.