If a2 + b2 + c2 = 941 and ab + bc + ca = 10, then a + b + c is
Choose the correct choice from the following options
A) 44 B) 56 C) 16 D) 32 E) 31

Rationale: "by formula , ( a + b + c ) ^ 2 = a ^ 2 + b ^ 2 + c ^ 2 + 2 ( ab + bc + ca ) , since , a ^ 2 + b ^ 2 + c ^ 2 = 941 and ab + bc + ca = 10 , ( a + b + c ) ^ 2 = 941 + 2 ( 10 ) = 961 = 31 ^ 2 therefore : a + b + c = 31 answer : e"
Answer: E