How did John Davidson Rockefeller get rich?

in the oil industry
by selling supplies to the army
by mining diamonds and gold
by building railroads
John Davison Rockefeller was the founder of the Standard Oil Company, which dominated the oil industry in the U.S. As kerosene and gasoline grew in importance, Rockefeller's wealth soared, and he became the world's richest man and first American worth more than a billion dollars.
correct this question
globalquiz.org
reach: rather globalAmericansculturefamous peoplehistoryindustrymillionariesRockefellerwealth
in the oil industry
by selling supplies to the army
by mining diamonds and gold
by building railroads
answers
flagSwitzerland
69%
13%
0%
17%
23
flagCroatia
65%
11%
3%
19%
26
flagthe United Arab Emirates
64%
16%
12%
8%
25
flagItaly
61%
12%
10%
16%
49
flagFrance
60%
8%
8%
18%
58
flagGermany
58%
12%
6%
21%
243
flagCanada
58%
16%
4%
20%
48
flagSpain
57%
5%
5%
23%
38
flagthe United States
55%
9%
8%
25%
561
flagthe United Kingdom
55%
13%
12%
19%
478
flagDenmark
54%
14%
0%
31%
35
flagNorway
54%
29%
4%
12%
24
flagBelgium
54%
18%
4%
22%
22
flagPoland
52%
14%
10%
22%
15534
flagthe Netherlands
50%
17%
8%
22%
67
flagUnknown
47%
10%
11%
29%
746
flagSweden
44%
12%
4%
36%
25
flagAustralia
42%
14%
5%
37%
35
flagRepublic of Ireland
38%
14%
8%
35%
67
flagIndia
32%
21%
22%
22%
119