Most of the information's required for answering this question is already given.
Percentage of people in the world having genetic defects = 4.5%
Total number of people screened = 1300
Number of people having defect = 1300 (4.5/100)
= 58.5
The number of people having the defect
but diagnosed wrongly not to have it = 58.5 (19/100)
= 11
From the above deduction, we can conclude that the correct option among all the options that are given in the question is the first option or option "a". I hope that the procedure is clear enough for you to understand.