Answer:

To solve this problem, we need to go through the sequence and identify the odd numbers that are immediately preceded and followed by an even number.

Given sequence: 5 1 4 7 3 2 5 6 8 9 6 7 3 2 1 5 6 4 3 2 7 4

Step 1: Identify the odd numbers in the sequence

The odd numbers in the sequence are: 5, 1, 7, 3, 5, 9, 7, 3, 1, 5, 3, 7

Step 2: Check if each odd number is immediately preceded and followed by an even number

Let's go through each odd number one by one:

1) 5 is not immediately preceded and followed by an even number (1 is odd and 4 is even)
2) 1 is not immediately preceded and followed by an even number (5 is odd and 4 is even)
3) 7 is immediately preceded and followed by an even number (4 is even and 3 is even)
4) 3 is not immediately preceded and followed by an even number (7 is odd and 2 is even)
5) 5 is not immediately preceded and followed by an even number (3 is odd and 6 is even)
6) 9 is not immediately preceded and followed by an even number (8 is even and 6 is even)
7) 7 is not immediately preceded and followed by an even number (9 is odd and 6 is even)
8) 3 is not immediately preceded and followed by an even number (7 is odd and 2 is even)
9) 1 is not immediately preceded and followed by an even number (3 is odd and 5 is odd)
10) 5 is not immediately preceded and followed by an even number (1 is odd and 3 is odd)
11) 3 is not immediately preceded and followed by an even number (5 is odd and 7 is odd)
12) 7 is not immediately preceded and followed by an even number (3 is odd and 4 is even)

Step 3: Count the number of odd numbers that satisfy the condition

From the above analysis, we can see that there are 4 odd numbers in the given sequence that are immediately preceded and followed by an even number.

Therefore, the correct answer is option 'A' - 4.