The question tests the correct position under Section 80D of the Income Tax Act, 1961, when an assessee pays a medical insurance premium for himself and his family. Each option can be checked against what Section 80D actually provides.
Only the first option correctly reflects that the deduction exists but is bounded by the ceilings and conditions written into Section 80D; the other three options either wrongly deny the deduction, wrongly restrict it to one class of taxpayers, or wrongly claim it is unlimited.
So the correct answer is deduction is allowed subject to prescribed limits and conditions.