Answer:
B) they show which way iron shavings would align themselves
Explanation:
Let's analyze each statement:
A) they are not affected by their own source --> this is true for both magnetic and electric fields. In fact, both fields are produced (and so affected) by a source (a magnet or a current in the magnetic field case, and an electric charge in the electric field case)
B) they show which way iron shavings would align themselves --> this is only true for the magnetic field. In fact, the pieces of iron will align according to the magnetic field; however, since they are electrically neutral, they are not affected at all by an electric field.
C) they re stronger near the source and get weaker farther away --> true for both magnetic and electric fields.
D) the closer the fields lines, the stronger the fields --> also true for both magnetic and electric fields.
So, the correct answer is B.
