Answer:
a. Atlas.
Step-by-step explanation:
An atlas is a book of maps, a detailed picture of maps with different features. In other words, an atlas is a book of maps that one can use to look at other places and contains different features of the earth, be it the geographical features, the topography, the political boundaries, the railways, roadways, etc.
In order for Ana to get to her Grandmother's house safely by Christmastime, she can use the atlas to find out the way, the roads that she can take to the house. Through the map in the atlas, she will be able to figure out the path she has to take to reach from her home to her grandmother's place.
Thus, the correct answer is option a.