What Does It Mean When We Say That the Tails

Multiple Choice

What does it mean when we say that the tails of the normal curve are asymptotic to the x axis?

A) The tails get closer and closer to the x axis but never touch it.
B) The tails gets closer and closer to the x axis and eventually touch it.
C) The tails get closer and closer to the x axis and eventually cross this axis.
D) The tails get closer and closer to the x axis and eventually become this axis.