What type of overlap is involved in the formation of C-H bonds in acetylene molecules?

The carbon atoms in acetylene ($\mathrm{C_2 H_2}$) exhibit sp hybridization, resulting from two $σ$ bonds (one to hydrogen and one to carbon) and no lone pairs.

Each C–H $σ$ bond forms via overlap between a carbon sp hybrid orbital and hydrogen's 1s atomic orbital.

Reviewing the overlaps:

A) $sp^3$–$s$: characteristic of alkanes
B) $sp^2$–$s$: characteristic of alkenes
C) $sp$–$s$: correct for acetylene's C–H bonds
D) $sp$–$sp$: describes acetylene's C–C $σ$ bond

The C–H bonds in acetylene result from $sp$–$s$ overlap.