How many dots are needed, when the last word of the sentence is a.m.? [duplicate]

Example:

It's all about apples, oranges, bananas, etc.

VS.

It's all about apples, oranges, bananas, etc..

Update

What happens if the abbreviation is inside parentheses, do you place a dot after and before the closing parenthesis?

It's all about fruit (apples, bananas, etc.).

Solution 1:

The correct form of your example:

It’s all about apples, oranges, bananas, etc.

Jack Lynch’s Guide to Grammar and Style states:

This one is simple enough: never double up periods. If a statement ends with “etc.” the period in the abbreviation does double duty, serving as the full stop to end the sentence. If, however, you need another mark of punctuation after an abbreviation, you can put it after the period. So:

• This was her first trip to the U.S.
  (The period does double-duty, ending both the abbreviation and the sentence.)
• Is this your first trip to the U.S.?
  (The period ends the abbreviation, but the question mark ends the sentence.)
• On her first trip to the U.S., Kristina lost her passport.
  (The period ends the abbreviation, but the sentence keeps going after the comma.)

The only thing to remember: don't double the periods. Everything else is logical enough.

Solution 2:

If etc. occurs at the end of a sentence, then you do not add another period.

It's all about apples, oranges, bananas, etc.

However, if etc. occurs at the end of a clause, you can add a comma or other punctuation mark after it.

I bought the apples, oranges, etc., but they were all rotten.

Grammar.ccc.com gives the following rule:

When an abbreviation with a period ends a sentence, that period will suffice to end the sentence.