Who among the following individuals received a spot bonus? a$.$ Henry, a software engineer, who received a $$500$ gift certificate from his boss after he found a fix for a software bug that had been causing problems b$.$ Marnie, who received an additional $$1,000$ because a person whom she referred was hired by her company c$.$ Rumi, who received a higher paycheck than she did in the last month because of the sales commission she received on acquiring a new client d$.$ Georgia, a financial analyst, who received $$1,000$ over and above her regular salary as a token of appreciation for her tenure in the company