The language Q has the following properties:
(1) ABC is the base word.
(2) If C immediately follows B, then C can be moved to the front of the code word to generate another word.
Which one of the following is a code word in language Q ?

Options

A. CAB
B. BCA
C. AAA
D. ABA

Answer

To solve the problem, we need to determine which of the given options is a valid code word in the language Q based on the properties provided. Let's break down the solution step by step.

### Step 1: Understand the Base Word
The base word given is "ABC". This means that any valid code word must be derived from this base word.

**Hint:** Always start by identifying the base word and its components.

### Step 2: Apply the Given Condition
The second condition states that if 'C' immediately follows 'B', then 'C' can be moved to the front of the code word. This means we can rearrange the letters if the condition is met.

**Hint:** Look for occurrences of 'BC' in the code words to see if the condition can be applied.

### Step 3: Check Possible Code Words
Now, we need to check each of the options provided (not listed in the question) to see if they can be derived from "ABC" using the condition.

1. **Example Option 1: CAB**
- In "CAB", 'C' follows 'B' (as 'B' is before 'A' and 'C' is at the front).
- According to the rule, we can move 'C' to the front, which gives us "CAB". Therefore, "CAB" is a valid code word.

2. **Example Option 2: ACB**
- In "ACB", 'C' does not immediately follow 'B'. Therefore, we cannot apply the condition here.

3. **Example Option 3: BCA**
- In "BCA", 'C' immediately follows 'B'. We can move 'C' to the front, resulting in "CAB", which is valid.

4. **Example Option 4: ABC**
- "ABC" is the base word itself and is valid.

### Step 4: Identify the Valid Code Words
From the analysis above, the valid code words derived from the base word "ABC" using the given condition are "CAB" and "BCA".

### Conclusion
Among the options provided, "CAB" is a valid code word in language Q.

**Final Answer:** The code word in language Q is **CAB**.