Which of the following will result in a compile-time error? float f = 1.3; char c = 'A'; byte b = 10; boolean b = true;

The first line float f = 1.3; will result in a compile-time error. In Java, by default, any decimal number is treated as a double. So, 1.3 is considered a double value and we are trying to assign it to a float variable which leads to a precision loss. To fix this, you should write it as float f = 1.3f; or float f = (float) 1.3;.

The other lines of code are correct. The second line char c = 'A'; is correct because 'A' is a valid character literal in Java. The third line byte b = 10; is correct because 10 is within the range of byte (-128 to 127). The fourth line boolean b = true; is correct because true is a valid boolean value in Java.