Answer: The antecedent to which the bold pronouns refer to is 'each person'
Step-by-step explanation:
An antecedent is an expression which gives its meaning to a proform (pronoun, pro-verb, pro-adverb, etc.) The antecedent usually precedes its proform.
In this particular example: Each person will donate HIS or HER own items for the charity bazaar, the proforms are pronouns 'his' and 'her', which are preceded by the antecedent, 'each person'.