What is the variation of ammeter reading with PQ
When the wiper is at P the resistance is (0Ω || 10Ω) + 1000Ω = 1000Ω. At Q it is 1000Ω || 10Ω ~= 10Ω. Therefore the resistance decreases as the wiper moves from P to Q, and subsequently the current increases. Therefore all graphs are potentially correct.

In order to determine which of the graphs is correct, write out the equation for the current in terms of the resistance and wiper position and plot it.