Past exam of the mathematics course of the University of Cambridge / 2024 / iii / Paper 114 / 1 / a

The quotient is obtained from its image $Z\cong S^1$ by attaching the interior of $D^2$. The boundary map winds $n$ times around $Z$, so this is the cyclic Moore space in dimension one $M(\mathbb{Z}/n,1)$. Its cellular chain complex isTherefore