The sum of the first $n$ terms of the series $3 + 33 + 333 + \ldots$ is —

• a$\dfrac{1}{27}\left(10^{n+1} - 9n - 10\right)$
• b$\dfrac{3}{9}\left(10^{n} - 1\right)$
• c$3n$
• d$\dfrac{1}{9}\left(10^{n+1} - 9n\right)$