The correct answer is b. grit
Step-by-step explanation:
The term "grit" refers to the quality of being perseverant and therefore being able to overcome obstacles to achieve goals. Due to this, someone with grit is someone who shows determination and resilience; additionally, some with grit will achieve his/her goals no matter how difficult this can be.
Samantha is an example of someone demonstrating grit because despite her situation as a single parent and full-time employee she is determined to return to school and achieve her goals. Also, she shows determination and resilience which are part of having grit because through these she can overcome obstacles in the process of achieving her goals.