To test whether two variables refer to the same object in memory, you should use the is operator. The is operator returns True if the two variables point to the same object in memory, and False otherwise.

For example:

a = [1, 2, 3]

b = a

c = [1, 2, 3]

print(a is b) # True

print(a is c) # False

In this example, a and b refer to the same list object in memory, so a is b returns True. On the other hand, a and c refer to two separate list objects with the same values, so a is c returns False.

The two true statements related to PEP 8 programming recommendations for code writing are Option B and Option D.

Option B is true because PEP 8 recommends making object type comparisons using the isinstance() method instead of comparing types directly 1.

Option D is true because PEP 8 recommends not writing string literals that rely on significant trailing whitespaces as they may be visually indistinguishable, and certain editors may trim them 1.

The json.dumps() function is used to convert a Python object into a JSON string 1. It takes Python data as its argument, such as a dictionary or a list, and returns a JSON string.