Your answer would be A. positive linear association.
If we break this phrase down, we first get "positive", which we can see is true here as the graph is ascending towards the top right, that is, going upwards and 'forwards'. This is how we recognise lines with positive slopes, such as 3x or (1/2)x.
The word "linear" means a straight line, you can sort of see the word "line" in it, and so this is also true as the trend line is straight.
