Mario (age 59) and his wife, Maria (age 51), contributed to a traditional IRA in 2023. Mario had earned income of $35,000 and was not covered by a retirement plan at work. Maria didn't have earned income and was not covered by retirement plan at work. What is the maximum total contribution allowed for both? Select one: O a. $14,000 O b. $13,000 O C. $15,000 O d, $ 7,500