Explanation:

- To find the unit digit of \( (57242)^{(9 \times 7 \times 5 \times 3 \times 1)} \), observe the unit digit of the base, which is 2.

- The powers of 2 repeat every 4 numbers: \( 2^1 = 2 \), \( 2^2 = 4 \), \( 2^3 = 8 \), \( 2^4 = 16 \) (unit digit 6), and then \( 2^5 = 32 \) (unit digit 2), repeating the same cycle.

- Calculate \( 9 \times 7 \times 5 \times 3 \times 1 = 945 \).

- Determine 945 modulo 4 to find its position in the cycle. \( 945 \div 4 = 236 \text{ remainder } 1 \).

- \( 2^1 \) has a unit digit 2. So, the unit digit of the expansion is 2.

Correct Answer: Option 1, 2