solve them please

Question 2 What is the error in the following code fragment? double[ ] data = new double[20]; data[20] = 15.25 O A. data not initialized O B. A two-dimensional array is required O c. Out-of-bounds error OD. A cast is required EL A Moving to another question will save this response. Question 4 What is the output of the following code fragment: int[] ar = {2.4.6.8 }; System.out.println( ar[0] + HR + ar[2] ); O A 48 O B.26 . 8 O D.24 A Moving to another question will save this response. Assume that we have a class Student. What is the default value of the elements in an array of student obiects after declaration and instanta of the array? points Anull B. string O c. undefined 0.0.0 A Moving to another question will save this response. FA % 5 0 4 E 3 2 R E E A Moving to another question will save this response. Question 7 How many columns does a have if it is created as follows: intol a = {{2, 4, 6, 8}. {1,2,3,4}};? O A. 2 O B.4 O 0.1 OD.3 A Moving to another question will save this response