Limits and continuity Which of the following statements are true, and which are false?...

Limits and continuity

Which of the following statements are true, and which are false? if true, say why; if false, give a counterexample (that is, an example confirming the falsehood).

a. If exists but does not exist, then does not exist.

b. If neither exists, then does not exist.

c. If f is continuous at x, then so is |f|.

d. If |f | is continuous at a, then so is f.