Six vectors \( \vec{a},\vec{b},\vec{c},\vec{d},\vec{e},\vec{f} \) have magnitudes and directions shown. Which statement is true?
\( \text{M} \xrightarrow{\text{CH}_3\text{MgBr}} \text{N} + \text{CH}_4 \uparrow \xrightarrow{\text{H}^+} \text{CH}_3\text{COCH}_2\text{COCH}_3 \)
Identify the ion having 4f\(^6\) electronic configuration.