TITLE: Which of the following sets has the greatest cardinality?(Math subject GRE exam 0568 Q.61 )
QUESTION [13 upvotes]: How can I solve this question in only 2.5 minutes? It must be solved using deep insight and intuition, which I do not have. Could anyone help me, please?
Thanks!


Which of the following sets has the greatest cardinality?
(A) $\mathbb{R}$
(B) The set of all functions from $\mathbb{Z}$ to $\mathbb{Z}$
(C) The set of all functions from $\mathbb{R}$ to $\{0, 1\}$
(D) The set of all finite subsets of $\mathbb{R}$
(E) The set of all polynomials with coefficients in $\mathbb{R}$

REPLY [2 votes]: These are also some important links for solving my question(at least from my point of view):
(A)$\mathbb R$ is uncountable
(B)What is the cardinality of the set of all functions from $\mathbb{Z} \to \mathbb{Z}$? 
(C)What is the cardinality of the set of all functions from $\mathbb{R}$ to {0,1}?
(D)Cardinality of the Set of all finite subset of $\mathbb{R}$
(E)Cardinality of the set of all polynomials with coefficients in $\mathbb R$