Correct Answer: frequently

Solution : The correct answer is option 3.

Explanation:

• - In the provided sentence, an adverb with a connotation similar to'regularly' is required.
• - 'Sometimes' indicates on occasion, not all of the time.
• - 'Seldom' indicates infrequently.
• - 'Frequently' means on a regular or habitual basis; frequently.
• - 'Rarely' means infrequently; infrequently.
• - As a result, to make the sentence grammatically correct, the word 'frequently' should be used.
• - As a result, the right answer is 'frequently'.

Correct sentence: I always check my sums because I frequently make mistakes.

• Adverbs are words that modify (describe) a verb (he sings loudly), an adjective (extremely tall), another adverb (ended too fast), or even a whole phrase (Fortunately, I had brought an umbrella).
• - Adverbs frequently end in -ly, however some (such as fast) appear identical to their adjective equivalents.