90. Which compound exhibits only two signals in its 1H NMR spectrum, a triplet and a quintet? (A) BrCH2CH2CH2Br (B) BrCH2CH2CH2Cl (C) (CH3)2CHCH(CH3)2 (D) CH3CH2CH2CH3 (E) (CH3)2CHOCH(CH3)2

3. For a specific CPU design, there are three instruction classes as depicted in Table 1 and run at a clock rate of 100 MHz. For a given program, a compiler can produce the following executed instruction counts as depicted in Table 2. Please calculate the average CPI of this compiler. (A) 4 (B) 2 (C) 1.25 (D) 0.5 (E) All of the above are wrong.

90. Which compound exhibits only two signals in its ¹H NMR spectrum, a triplet and a quintet?
(A) BrCH₂CH₂CH₂Br
(B) BrCH₂CH₂CH₂Cl
(C) (CH₃)₂CHCH(CH₃)₂
(D) CH₃CH₂CH₂CH₃
(E) (CH₃)₂CHOCH(CH₃)₂

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