What does the idiom 'horse sense' mean?

[Horsy]

English Idioms and Expressions, Elementary Level

ESL/EFL Test #9 "Animal Idioms", question 8

He never makes any silly mistakes because he's got too much horse sense.

(a) common sense
(b) nonsense
(c) absolute sense
(d) full sense

English Idioms and Expressions, Elementary Level

ESL/EFL Test #9 "Animal Idioms", answer 8

He never makes any silly mistakes because he's got too much common sense.

Correct answer: (a) common sense
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In what way absolute goes in less attention than of common in the speakers mind specially when he is guessing meaning of an idiomatic like this one.

[Yankee]

Hi

To get this test right, you need to know both the idiom "horse sense" and the standard collocation "common sense":
http://www.bartleby.com/61/59/C0515900.html
.
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"Nearly all men can stand adversity, but if you want to test a man's character, give him power." ~ Abraham Lincoln