A topic sentence is, by definition, a controlling idea, so
we can safely assume “A” is not what is missing because this sentence is a
topic sentence. Because a topic sentence
is generally one of the first sentences in a paragraph, we know it is not
missing a concluding idea because that would appear toward the end of a
paragraph, so we know "C" is not the answer. We can further determine that
support for the main point is not missing from the topic sentence because
support for the main point would appear following the topic sentence within the
body of the paragraph, so we know "D" is not the answer. What is missing,
however, is a limited topic. The way
things currently stand with “Giving holiday gifts can be expensive!” is a bit broad (almost too vague) which means
there is potentially so much that can be covered that anything covered will be
too superficial and underdeveloped. By
limiting the scope and narrowing the topic by, for instance, specifying the
holiday, the types of presents, or the cost, one would be able to provide a
well-developed and focused paragraph.
This part of the excerpt seems to be correct as it reveals that the diet alone is responsible for his ninth birthday: "It had plenty of room to expand, thanks to the spare diet of the establishment; and perhaps to this circumstance may be attributed his having any ninth birth-day at all."
