Why Does a DNA Strand Grow Only in the 5ʹ

Why does a DNA strand grow only in the 5ʹ to 3ʹ direction?

A) because DNA polymerases can only add nucleotides to the 3ʹ end of the growing molecule
B) because DNA polymerases can only add nucleotides to the 5ʹ end of the growing molecule
C) because the DNA molecule only unwinds in the 5ʹ to 3ʹ direction
D) because DNA polymerase requires the addition of a starter nucleotide at the 5ʹ end