The question revolves around the time periods of India`s Five-Year Plans, specifically the Sixth, Seventh, and Eighth plans.

Option 1 suggests the Seventh Plan covered 1987-92. This seems incorrect because it directly follows the suggested ending of the Sixth Plan in 1985 and doesn`t provide any gap.

Option 2 states the Seventh Plan covered 1986-91. However, this can`t be right as the Sixth plan ends in 1985 and again there`s no gap before the start of the next plan.

Option 3, the correct answer, states that the Seventh Plan covered 1985-90. With this option, the Seventh plan correctly starts right after the end of the Sixth Plan in 1985 and provides a two-year gap before the Eighth Plan in 1992 allowing for a break in planning due to unforeseen country`s economic situations between 1990-1992.

Option 4 suggests the Seventh Plan covered 1998-94. This doesn`t fit, as it starts three years after the end of the Sixth Plan and two years before the beginning of the Eighth Plan. This would mean an overlap which is not possible as per the Five-Year Plan structure.