Here is an alternative using the tasks package:

\documentclass{article}
\usepackage{tasks}
\setlength{\parindent}{0pt}
\begin{document}
\textbf{Question}: Here is the question text. Answers are arranged in 4 columns.
\begin{tasks}(4)
\task first answer
\task second answer
\task third answer
\task fourth answer
\end{tasks}
\bigskip
\textbf{Question}: Here is the question text. Answers are arranged in 2 columns.
\begin{tasks}(2)
\task first answer
\task second answer
\task third answer
\task fourth answer
\end{tasks}
\bigskip
\textbf{Question}: Here is the question text. Answers are arranged in 2 columns and are longer than a single line.
\begin{tasks}(2)
\task first answer first answer first answer first answer
\task second answer second answer second answer
\task third answer
\task fourth answer
\end{tasks}
\end{document}
If you want your answer to spread across the whole textwidth, you could use tabularx as follows: (The red vertical lines indicate the width of the textblock). Please note that with this method, the spaces between the first and second , as well as between the second last and the last column will be bigger than the spaces between the other columns. (See also this comment)

\documentclass{article}
\usepackage{tabularx}
\setlength{\parindent}{0pt}
\begin{document}
\textbf{Question}: Here is the question text. Answers are arranged in 4 columns and take up the entire textwidth.
\begin{tabularx}{\textwidth}{@{}X>{\centering\arraybackslash}X>{\centering\arraybackslash}X>{\raggedleft\arraybackslash}X@{}}
\textbf{A} first answer &
\textbf{B} second answer &
\textbf{C} third answer &
\textbf{D} fourth answer
\end{tabularx}
\end{document}
Using tabular* in combination with \extracolsep{\fill} one can achieve the following output.Here, the horizontal white spaces between adjacent columns will be equal. If your answers are too long and need a linebreak, you might want to switch to p type columns instead. Please also note, that with this method, the width each answer takes up is different.

\documentclass{article}
\setlength{\parindent}{0pt}
\begin{document}
\textbf{Question}: Here is the question text. Answers are arranged in 4 columns and take up the entire textwidth.
\setlength{\tabcolsep}{0pt}
\begin{tabular*}{\textwidth}{@{\extracolsep{\fill}}ccccc}
\textbf{A} 1 &
\textbf{B} 2 &
\textbf{C} 3 &
\textbf{D} 4 &
\textbf{E} 5
\end{tabular*}
\begin{tabular*}{\textwidth}{@{\extracolsep{\fill}}ccccc}
\textbf{A} 1 &
\textbf{B} 2 &
\textbf{C} 3 &
\textbf{D} 4 &
\textbf{E} longer text
\end{tabular*}
\begin{tabular*}{\textwidth}{@{\extracolsep{\fill}}ccccc}
\textbf{A} 1 &
\textbf{B} long text &
\textbf{C} 3 &
\textbf{D} 4 &
\textbf{E} longer text
\end{tabular*}
\end{document}
\makebox[\dimexpr \linewidth/5][l]{...}for each answer. There is also tabularx with 5 X columns. – John Kormylo Aug 18 '19 at 00:44