“…single-hop QA [2,12,33,60,103,132], open-domain QA [184], medical QA [68,88] etc. The surveys that are most relevant to MHQA are the ones focused on QA over knowledge bases [32,43,82] and visual QA [88,135,164]. However, these can be considered as sub-domains of the more general formulation of MHQA field that this manuscript aims to survey.…”