Kahlil Wants to Be Able to Run a Marathon by the End

Kahlil wants to be able to run a marathon by the end of the spring. What does research suggest will be the best way for him to achieve his goal?

A) focus on concrete steps throughout the entire season
B) focus on the abstract goal throughout the entire season
C) begin with a set of concrete steps in mind, and then gradually shift his focus towards the abstract goal
D) begin with a focus on the abstract goal, and then gradually shift his focus towards a set of concrete steps