If (a + b - 1)2 + (b + c - 9)2 + (c + a - 4)2 ≤ 0, then the value \(\sqrt {{{\left( {a + b} \right)}^{c\;}} + {{\left( {c + a} \right)}^b} - 1} \) is∶

• A. 9
• B. 6
• C. 7
• D. 8