The problem in the sentence "James is more smarter than Steven", is option A. Double Comparison. Double comparison happens when we use the word more or less plus the comparative form of an adjective with the suffix -er.
When adding a suffix that begins with a vowel to a root word that ends with a consonant, double the consonant before adding the suffix. When adding a suffix to the end of a word, always double the last letter of the root word before adding the suffix.
