Consider the following expression: $x[i] = (p + r) * -s[i] + u/w$. The following sequence shows the list of triples representing the given expression, with entries missing for triples (1), (3), and (6). Which one of the following options fills in the missing entries CORRECTLY?

In three-address code represented via triples, each entry has three fields: (op, arg1, arg2), and intermediate values are referenced by their triple indices (such as (0), (1), etc.).

Let us break down the evaluation of the expression $x[i] = (p + r) * -s[i] + u/w$ step-by-step:

1. Triple (0): Evaluates $p + r$

   $$(0) \quad + \quad p \quad r$$

2. Triple (1): Array access / dereference for $s[i]$ (reading an array element into a temporary value uses the operator =[]):

   $$(1) \quad =[] \quad s \quad i$$

3. Triple (2): Computes unary minus of $s[i]$:

   $$(2) \quad \text{uminus} \quad (1)$$

4. Triple (3): Multiplies $(p + r)$ with $-s[i]$, which corresponds to multiplying the result of triple (0) with triple (2):

   $$(3) \quad * \quad (0) \quad (2)$$

5. Triple (4): Computes $u / w$:

   $$(4) \quad / \quad u \quad w$$

6. Triple (5): Adds the two terms $(p + r) * -s[i]$ and $u / w$:

   $$(5) \quad + \quad (3) \quad (4)$$

7. Triple (6): Specifies the array target location $x[i]$ for assignment (using the indexed assignment operator []=):

   $$(6) \quad []= \quad x \quad i$$

8. Triple (7): Assigns the final expression value in (5) to the array location specified by (6):

   $$(7) \quad = \quad (6) \quad (5)$$

Thus, the missing entries are:

• (1):=[] s i

• (3):* (0) (2)

• (6):[]= x i

This matches Option (A).