From Longman Dictionary of Contemporary Englishdecide on/upon something phrasal verbCHOOSEto choose something or someone after thinking carefully Have you decided on a date for the wedding? → decide→ See Verb table
Examples from the Corpus
decide on/upon • Weekend retreats were decided on and Courtfield was the obvious venue for the South West.• And she can decide on her own if she wants to use contraceptives.• How this dosage of epoetin was decided upon is not mentioned.• Local authorities no longer have the discretion to decide on rebates, and the rebates are very limited.• That includes deciding on rental terms or arranging for others to make repairs.• The advisory committee which decided on research and development money for renewable energy was dominated by nuclear proponents.• If two laws conflict with each other, the courts must decide on the operation of each.• The first task was to decide on who owns what. 