Check my which topic is suitably limited for a research paper?
a. the history of baseball and its greatest players
b. the home run record and batting average of lou gehrig ★★★
c. why lou gehrig was forced to resign from baseball
d. how lou gehrig overcame difficulties to become one of baseball's greatest players

i chose b because there isn't much to talk about (limited). is this right? can someone explain if it's wrong?