Answer:
a.Remove
Explanation:
Since there are extra characters in the string for example:-222-33-4444 we need 222334444 so there are two extra characters in the string and they are "-".So we need to remove extra characters from the string to get the final string.We cannot replace - since it has to be replaced by another character which will give the wrong string.Trim is used to remove leading and trailing spaces from the string. Substring provide another smaller string created from the original string.