BNF: ets 1999 sample booklet question 26

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Stuck on these:

Question 26.
Expressions in a certain language can be described in Backus-Naur form as follows:
Expr = Term | Expr op1 Term
Term= Item | Term op2 Item
Item = variable | number

This syntax is most appropriate when the order of evaluation is
(A) from left to right always
(B) from left to right, but op1 takes precedence over op2
(C) from left to right, but op2 takes precedence over op1
(D) in any order, but op1 takes precedence over op2
(E) from right to left always

Answer:

SPOILER: C

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Question 24.
Deduction in Prolog is based on the concept of unification. Two expressions E and F are said to be unifiable if there are substitutions for the variables of E and F that make the expressions lexically identical. In the following three expressions, only W, X, Y, and Z are variables.
I. f (W, W)
II. f (X, 1)
III. f (Y, g(Z))
Which of these expressions is (are) pairs of unifiable expressions?
(A) (I, II) only
(B) (I, III) only
(C) (II, III) only
(D) (I, II) and (I, III) only
(E) (I, II), (I, III), and (II, III)

Answer:

SPOILER: D

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Questions 30-32 : Digital logic multiplication / parallel adder ?
Edit - For a similar circuit, see this link:

SPOILER: ecen3233.okstate.edu/PDF/Combinational%20Multiplier.pdf

The '99 booklet can be found in Files section of yahoo grecs group.