3. If $\mathrm { a } _ { 1 } \mathrm { a } _ { 2 } , \ldots , \mathrm { a } _ { \mathrm { n } }$ are positive real numbers whose product is a fixed number c , then the minimum value of $a _ { 1 } + a _ { 2 } + \ldots + a _ { n - 1 } + 2 a _ { n }$ is\\
(A) $\quad n ( 2 c ) ^ { 1 / n }$\\
(B) $\quad ( n + 1 ) c ^ { 1 / n }$\\
(C) $\quad 2 \mathrm { nc } ^ { 1 / \mathrm { n } }$\\
(D) $\quad ( n + 1 ) ( 2 c ) ^ { 1 / n }$\\