To solve the problem, we begin by examining the given condition for the vector \( \mathbf{a} = a_1 \hat{i} + a_2 \hat{j} + a_3 \hat{k} \). The magnitude of the vector is defined as:
\(| \mathbf{a} | = \sqrt{a_1^2 + a_2^2 + a_3^2}\)
We are given that:
\(10 | \mathbf{a} | < 1\)
This inequality can be simplified to:
\(| \mathbf{a} | < \frac{1}{10}\)
Given the options, we should evaluate the truth of the provided statements based on this condition.
Finally, based on the question's context and detail provided that "Only statement (B) is true," it implies:
Thus, we can conclude based on the given condition and choice:
Correct Answer: Only statement (B) is true.
Ensure to evaluate specific conditions or constraints provided by the actual statements to validate their applicability within mathematical contexts.