The question requires identifying the options where the code snippet correctly follows the described PEP 8 recommendation for whitespace.

Option A correctly states that there should be no whitespace before the parenthesis in a function call (spam(1)), which is a standard PEP 8 rule.

Option C correctly states that there should be no whitespace between a trailing comma and a closing parenthesis, which is essential for creating single-element tuples like foo = (0,). This also adheres to PEP 8.

Both options present a valid PEP 8 rule and a code snippet that correctly implements it.

Option B: The description is incorrect. PEP 8 explicitly advises against whitespace before a comma, semicolon, or colon. The provided code snippet demonstrates this incorrect practice.

Option D: The description is incorrect. PEP 8 recommends no whitespace immediately inside brackets for indexing or slicing. Although the code snippet (dct['key']) is correct, the accompanying textual rule is wrong, making the option invalid.

1. Python Enhancement Proposals, PEP 8 -- Style Guide for Python Code. This is the official style guide.

For A & D: In the "Pet Peeves" section, it states: "Avoid extraneous whitespace... Immediately before the opening parenthesis that starts the argument list of a function call: Yes: spam(1)... Immediately inside parentheses, brackets or braces: Yes: spam(ham[1], {eggs: 2}) No: spam( ham[ 1 ], { eggs: 2 } )". This confirms A is correct and the description in D is incorrect.

For B: The "Pet Peeves" section states: "Avoid extraneous whitespace... Immediately before a comma, semicolon, or colon: Yes: if x == 4: print(x, y); x, y = y, x No: if x == 4 : print(x , y) ; x , y = y , x". This confirms the description in B is incorrect.

For C: The "Pet Peeves" section states: "Avoid extraneous whitespace... Between a trailing comma and a following closing parenthesis. Yes: foo = (0,) No: bar = (0, )". This confirms C is correct.

Source: van Rossum, G., Warsaw, B., & Coghlan, N. (2001). PEP 8 -- Style Guide for Python Code. Python Software Foundation. https://peps.python.org/pep-0008/#pet-peeves

2. MIT OpenCourseWare, 6.0001 Introduction to Computer Science and Programming in Python, Fall 2016, Style Guide.

The guide, under the "Whitespace" section, specifies rules derived from PEP 8: "Don't use spaces in the following places: ... Immediately before an opening parenthesis that starts the arguments of a function call. ... Immediately before a comma or a colon. ... Immediately inside of parentheses, brackets, or braces." This supports the reasoning for A, B, and D.

Source: MIT OpenCourseWare. (2016). Style Guide for 6.0001. https://ocw.mit.edu/courses/6-0001-introduction-to-computer-science-and-programming-in-python-fall-2016/pages/readings/style-guide-for-6-0001/