Iff(x) andg(x) are continuous for all real numbersx, then which of the following isnotnecessarily true?

a.f(x) +g(x)is continuous for all real numbersx.

b.f(x) -g(x)is continuous for all real numbersx.

c.f(x) g(x)is continuous for all real numbersx.

d.f(x)/g(x) is continuous for all real numbersx.

e.f(g(x)) is continuous for all real numbersx.

Please show how to get the answer, I am very confused and can't figure it out