question:  Although Billy-boy questioned his decision of letting Grannie Annie leave with Baker in the kit car, what put his mind at ease?
context: DOUBLE TROUBLE by CARL JACOBI Grannie Annie, that waspish science-fiction writer, was in a jam again. What with red-spot fever, talking cockatoos and flagpole trees, I was running in circles—especially since Grannie became twins every now and then. Grannie Annie strode in the lead, her absurd long-skirted black dress looking as out of place in this desert as the trees. He could be excused this time, however, for this was only our third day on Jupiter's Eighth Moon, and the country was still strange to us. But Miss Flowers, known to her friends as Grannie Annie, had always been mildly crazy. Grannie Annie was the original research digger-upper, and when she laid the setting of a yarn on a star of the sixth magnitude, only a transportation-velocity of less than light could prevent her from visiting her "stage" in person. He was an old prospector Grannie had met, and he had become so attached to the authoress he now followed her wherever she went. As for Xartal, he was a Martian and was slated to do the illustrations for Grannie's new book. So now here we were at the outer reaches of the Baldric, four travelers on foot with only the barest necessities in the way of equipment and supplies. And then all at once Grannie stopped again, this time at the top of a high ridge. She offered no further explanation, but a quarter of an hour later as we topped another rise a curious elliptical car with a long slanting windscreen came into view. Attached to its hood was a taut wire which slanted up into the sky to connect with the kite. Five minutes later Grannie was shaking his hand vigorously and mumbling introductions. Occasionally he touched a stud on an electric windlass to which the kite wire was attached. Apparently these adjustments moved planes or fins on the kite and accounted for the car's ability to move in any direction. As Jimmy Baker led the way up the inclined ramp, a door in the central building opened, and a man emerged.
output:  The invention by Baker allowed them to watch the movements of the car and its passengers
options:  The car and its passengers were safe from the Red Spot Fever  The kite car was protected by the strange birds.  The invention by Baker allowed them to watch the movements of the car and its passengers  She was a strong woman and capable of taking care of herself.