The correct answer is S-V-O.
S-V-O stands for Subject-Verb-Direct Object. If you take a look at the sentence above, you will see that Jim is the subject, gladly accepted is the verb, and the price of $100 is the direct object. The easiest way to determine whether something is a direct object or not is simply to ask - what.
For example: What did Jim gladly accept? - And the answer is The price of $100.
S-V-I-O stands for Subject-Verb-Indirect Object; S-V-A stands for Subject-Verb-Predicate Adjective; S-V-N stands for Subject-Verb-Predicate Nominative, none of which appear in this sentence.
