Zhu, Y. et al. 2026. MoHoBench: Assessing Honesty of Multimodal Large Language Models via Unanswerable Visual Questions. Proceedings of the AAAI Conference on Artificial Intelligence. 40, 34 (Mar. 2026), 29205–29213. DOI:https://doi.org/10.1609/aaai.v40i34.40159.