Grammatically Correct: The writer's essential guide to punctuation ...

In Part II of the exam, answer questions A and B, or C.
PUNCTUATION
It may also sometimes be beneficial to break up a clause that is
long or complex, even if not ambiguous. Skilled writers have a feel
for when a comma would be a good idea, even when it isn't required
according to the strict rules. Basically, you should consider putting
a comma within a clause any time you sense that doing so would
make the sentence easier for readers to follow.
Exceptions aside, if commas aren't normally used within clauses,
where do they go?
First, the no-comma rule applies only when there are no more
than two parts to a compound subject or two subunits of any part
of the predicate. Commas are needed within a clause whenever
there are three or more such parts, or two or more adjectives in
front of a noun. This is described in "Separating Elements in a
Series" on page 79. Second, commas are needed within a clause if
it contains any embedded parenthetical text. This is described in
"Setting Off Parenthetical Elements" on page 71. Third, commas
are used to separate clauses from each other and to separate clauses
from other elements in the sentence. These scenarios are described
in the next section.
SEPARATING THE MAIN ELEMENTS
OF A SENTENCE
What's the difference between the following two sentences?
They settled only the budget issues, and work schedules and technical
matters had to be tabled until the next meeting.
They settled only the budget issues and work schedules, and technical
matters had to be tabled until the next meeting.
In case A, only the budget was settled; work schedules and technical
matters had to be tabled. In case B, the budget and work schedules
were settled, and technical matters had to be tabled.
When sentences contain multiple chunks of information, the boundaries
between these chunks must be clear. Commas clarify precisely
where one unit ends and the next begins. The syntax-the order in
which the words appear-is not always a sufficient cue, because the
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