Carol wants to choose a strong password for her computer. Which of the following should she include in her password?

A.
A mixture of uppercase and lowercase letters, symbols and numbers

B.
An arcane phrase only she can remember

C.
An incorrect spelling of a word or a phrase

D.
A mixture of random words that form non-sense
1D0-470

Explanation:
By mixing case, and combining it with non-characters will develop a complex password that cannot be easily cracked. If you used either lower case or upper case, then each position would require 27 different variations (26 letters and a blank). If you mix upper and lower case, then it is 53 (26 upper, 26 lower, and a space). Now add in numbers, and it is 63. Add in special characters and that number increases (exact number varies based on what special characters the system will allow in the password field). The increase in possible variations of one position of the password makes the solution space for the brute force attack exponentially large.
Incorrect Answers:
B: A phrase will contain valid words, which make the password crackable using a dictionary attack.
C: Even with an incorrect work spelling, dictionary attacks will vary the words in the dictionary to test words close to the correct spelling.
D: A phrase will contain valid words, which make the password crackable using a dictionary attack.