Research studies conducted by Heine and Lehman (2004) concerning the relationship between self-esteem and acculturation revealed which of the following patterns?
a. Acculturation had no significant impact on self-esteem levels.
b. Higher levels of acculturation were associated with higher self-esteem.
c. Higher levels of acculturation were associated with lower self-esteem.
d. The relationship between acculturation and self-esteem varied depending on cultural background.