The question 1: A defines a pointer p, which points to the first address of the array, and p+5 points to a[5].

There is no answer to the second question: int *q[5] defines a pointer array, but there is no definition with the same meaning in the answer, and the fourth answer means that a pointer to a 2-dimensional array is defined, where the column width is 5. You can ask specifically.

Question 3: D is the same as the first question.

Question 4: B sizeof is an operator, which means to get the size (number of bytes) of float type and return an integer.