A. 15 zeros
B. 18 zeros
C. 21 zeros
D. None of these
Thousand, Million, Billion, Trillion, Quadrillion, Quintillion-each comes with three additional zeroes. Even though there are names beyond Quintillion.
The numbers are written with scientific notation to make them easier to read and understand.
| Name | Number | 
| Million | 1 x 106 | 
| Billion | 1 x 109 | 
| Trillion | 1 x 1012 | 
| Quadrillion | 1 x 1015 | 
| Quintillion | 1 x 1018 | 
| Sextillion | 1 x 1021 | 
| Septillion | 1 x 1024 | 
| Octillion | 1 x 1027 | 
| Nonillion | 1 x 1030 | 
| Decillion | 1 x 1033 | 
| Undecillion | 1 x 1036 | 
| Duodecillion | 1 x 1039 | 
| Tredecillion | 1 x 1042 | 
| Quattuordecillion | 1 x 1045 | 
| Quindecillion | 1 x 1048 | 
| Sexdecillion | 1 x 1051 | 
| Septendecillion | 1 x 1054 | 
| Octodecillion | 1 x 1057 | 
| Novemdecillion | 1 x 1060 | 
| Vigintillion | 1 x 1063 | 
| Unvigintillion | 1 x 1066 | 
| Duovigintillion | 1 x 1069 | 
| Trevigintillion | 1 x 1072 | 
| Quattuorvigintillion | 1 x 1075 | 
| Quinvigintillion | 1 x 1078 | 
| Sexvigintillion | 1 x 1081 | 
| Septenvigintillion | 1 x 1084 | 
| Octovigintillion | 1 x 1087 | 
| Nonvigintillion | 1 x 1090 | 
| Trigintillion | 1 x 1093 | 
| Untrigintillion | 1 x 1096 | 
| Duotrigintillion | 1 x 1099 | 
| Ten-duotrigintillion (or Googol) | 1 x 10100 | 
| Skewer’s Number | 1 x 10130 | 
| Centillion | 1 x 10303 | 
| Googolplex | 1 x 1010100 |