Consider the following activities:
Spraying pesticides on a crop field
Inspecting the craters of active volcanoes
Collecting breath samples from spouting whales for DNA analysis
At the present level of technology, which of the above activities can be successfully carried out by using drones?
a. 1 and 2 only
b. 2 and 3 only
c. 1 and 3 only
d. 1, 2 and 3