The correct answer is option 1, "I".

In this sequence, the figures are represented by Roman numerals. The given options are Roman numerals, and we need to find the next figure in the sequence.

Looking at the given sequence, the first figure is represented by the Roman numeral "I". Based on the pattern, the next figure is expected to be represented by the next Roman numeral in ascending order.

Option 2, "II", is the next Roman numeral after "I", but it does not fit the pattern because it is skipping a number.

Option 3, "III", and Option 4, "IV", are also incorrect because they are not the next Roman numeral after "I".

Therefore, the correct answer is option 1, "I", as it follows the pattern of ascending order for Roman numerals in the given sequence.