Articulation errors:

A. cannot be fixed
B. should be constantly corrected
C. are frequently outgrown
D. occur as children try to imitate
new sounds.

Would the best answer be:
(D) occur as childrentry to imitate
new sounds?

D is probably the best answer; C is a good answer, too, but D is better, I think.

=)

Since this is not my area of expertise, I searched Google under the key words "articulation errors" to get these possible sources:

http://www.kidsource.com/ASHA/articulation.html
(Broken Link Removed)
http://www.hsdc.org/News/Speech/childarticulate.htm
http://www.pspawa.com.au/html/articulation.html

These should help you decide. In the future, you can find the information you desire more quickly, if you use appropriate key words to do your own search.

I hope this helps a little more. Thanks for asking.