Three of the following four letter-clusters are alike in a certain way and one is different. Pick the odd one out.

Directions: In the following question four words have been given, out of which three are alike in some manner and the for one is different. Choose out the odd one.

Directions: In the following question four words have been given, out of which three are alike in some manner and the for one is different. Choose out the odd one.

In the following question select the odd number from the given alternatives.

In the following question, select the odd letters from the given alternatives.

In the following question select the odd word from the given alternatives.

Directions: In the following question four words have been given, out of which three are alike in some manner and the for one is different. Choose out the odd one.
Triangle
Rectangle
Circle
Square 

Select the set that is different among the given four options.