Question: Who is Diosdado Macapagal Arroyo's maternal grandfather?
Sentence (from "Gloria Macapagal Arroyo"): Born as the daughter of President Diosdado Macapagal, Arroyo is a former professor of economics at Ateneo de Manila University where her eventual successor President Benigno Aquino III was one of her students.
Relevant evidence: Yes