Which of the Following Describes the Orbital Overlap of The \mathrm{C}(1)-\mathrm{C}(2)

Which of the following describes the orbital overlap of the $\mathrm{C}(1) -\mathrm{C}(2)$ sigma bond of 1-butyne, shown below?

A) $\mathrm{sp}-\mathrm{sp}$
B) $\mathrm{sp}^{2}-\mathrm{sp}^{2}$
C) $\mathrm{sp}^{3}-\mathrm{sp}^{3}$
D) $2 \mathrm{p}-2 \mathrm{p}$