The line crosses the y-axis at y=4, so will have an equation of the form
... y = (something)·x + 4
The line rises from left to right, so has a positive slope. That is, the "(something)" must be greater than zero.
The only selection that meets these criteria is
... B y = 2x + 4
3.7kg is also equal to 3700 grams
3700+620 grams
= 4320 grams
= 4320/1000 kg
= 4.32 kg