If S - T means that S is the mother of T, S × T means that S is the father of T, S + T means that S is the sister of T, then which of the following expression shows that P is the mother of R?

P - Q + R

Checking from the options, we get the answer from the option (ii): 

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Please note:

  l   ⇒ Vertical line shown "generation gap".

 =  ⇒ Double lines shown "relation of spouse" 

—  ⇒ Horizontal line shown "relation in same generation other than spouse".

     ⇒ Rectangular box shown " Male".

     ⇒ Circular box shown " Female".

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