Rearrange the following sentences in the proper sequence to form a meaningful paragraph; then answer the questions given below them.

(A) He discovered many patients were diagnosed before turning 65.
(B) Recently, scientists found a genetic marker tied to early-onset Alzheimer’s.
(C) Alzheimer’s is a brain disorder that damages memory and thinking over time.
(D) Using this lead, Rohan studied data from 48 states in the USA.
(E) This result points to the need for early detection and preventive therapy.
(F) This gradual decline is made worse because most treatments only manage symptoms.

Which of the following should be the LAST sentence after rearrangement?

To determine the correct sequence of sentences, let us analyze the logical links between them:
1. Sentence (C) serves as the introduction by defining Alzheimer's disease ("Alzheimer’s is a brain disorder that damages memory and thinking over time").
2. Sentence (F) links directly to (C) by using the phrase "This gradual decline" to refer to the progressive damage to memory and thinking described in (C). Therefore, (F) follows (C).
3. Sentence (B) introduces new scientific research, stating that scientists recently found a genetic marker tied to early-onset Alzheimer’s.
4. Sentence (D) states, "Using this lead, Rohan studied data...". The phrase "this lead" refers to the genetic marker discovered in (B). Thus, (D) follows (B).
5. Sentence (A) provides the finding of Rohan's study ("He discovered many patients were diagnosed before turning 65"). The pronoun "He" refers back to Rohan, so (A) follows (D).
6. Sentence (E) concludes the paragraph by discussing the implication of the finding: "This result points to the need for early detection and preventive therapy." The phrase "This result" refers to the discovery mentioned in (A).

The correct logical order of the sentences is C - F - B - D - A - E.

Therefore, the sentence that should be the LAST sentence after rearrangement is E.