Problem Solving (PS) | A palindrome is a number that reads the same forward and backward. For

A palindrome is a number that reads the same forward and backward. For example - 1331. How many 4-digit palindromes can be formed using two of the five digits - 1, 3, 5, 7, and 9?

A. 10
B. 20
C. 30
D. 40
E. 60

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