Final answer:
Charlotte's marriage to Mr. Collins removes him as a potential suitor for Elizabeth, which may lead to her future happiness.
Step-by-step explanation:
Charlotte's marriage to Mr. Collins may be helpful to Elizabeth's future happiness because it removes Mr. Collins as a potential suitor for Elizabeth. By marrying Mr. Collins, Charlotte takes herself out of the running as a potential partner for Elizabeth, ensuring that Elizabeth will not have to enter into a marriage with a man she does not love or respect. This allows Elizabeth to pursue other potential partners who may bring her more happiness.