P : as environment tools Q : for military purposes R : are finding various new uses S : the world’s fastest computers initially conceived The Proper sequence should be:

PQRS
QPSR
RPSQ
SQRP

The correct answer is: A. PQRS

The world’s fastest computers were initially conceived for military purposes. However, they are now finding various new uses, such as as environment tools.

Option B, QPSR, is incorrect because the sentence should start with the main idea, which is that the world’s fastest computers were initially conceived for military purposes. Option C, RPSQ, is incorrect because the sentence should not end with the main idea. Option D, SQRP, is incorrect because the sentence should not start with a subordinate clause.