The stream function of a doublet with horizontal axis and of strength μ is

• A. \(\frac{{\rm{\mu }}}{{2\pi }}{\rm{r}}\)
• B. \(\frac{{\rm{\mu }}}{{2\pi r}}{\rm{cos\theta }}\)
• C. \(\frac{{\rm{\mu }}}{{2\pi }}r{\rm{sin\theta }}\)
• D. \(\frac{{\rm{\mu }}}{{2\pi }}\frac{{{\rm{sin\theta }}}}{r}\)