Which is the safest method to choose a pivot element in

Statements:All hotels are buses.

Some buses are cars.

All cars are trams.

Some trams are clouds.

Statements:

No lessons are topics.

All topics are headings.

Some headings are introductions.

Statements:

Only hands are legs

Few hands are arms

All arms are shoulders

Conclusions:

Statements:                          

All jacket are coat.

All coat are blazzers.

Statements:

A few spine is leg.

No leg is hand.

All hand is arm.

Only arm is shoulder.

Conclusions:

Statement:  

All circles are bangle.

Mostly squares are bangle.

At-least some bangle are heart.

Conclusion:

Statements:

All clouds are earths.

No earth is a planet.

Conclusions:

I. No cloud is a planet.

Statement : Some towers are pillars.

Some pillars are buildings.

All buildings are flats.

No flat is a house.

Statements:

All Letters are Alphabets

Only few Letters are Numbers

All Digits are Alphabets

Conclusion: