What did Blanchard & Oswald's 2004 study find about the relationship between sexual behavior and happiness?Select an answer and submit. For keyboard navigation, use the up/down arrow keys to select an answer.aPeople who engage in same-sex sexual behavior are happier than people who engage in cross-sex sexual behavior.bPeople with higher incomes have sex more frequently.cPeople with higher education have higher levels of happiness from sexual encounters.dPeople with higher incomes have more sexual partners.