If a x 10^n is scientific notation, then a must be between 1 and

a) 10

b) 100

c) n

  A)  10

Step-by-step explanation:

In the US, a number in scientific notation will have a mantissa (a) such that ...

  1 ≤ a < 10

That is, the value of "a" must be between 1 and 10 (not including 10).

Comment on alternatives

In other places or in particular applications (some computer programming languages), the standard form of the number may be a×10^n with ...

  0.1 ≤ a < 1

In engineering use, the form of the number is often chosen so that "n" is a multiple of 3, and "a" is in the range ...

  1 ≤ a < 1000

This makes it easier to identify and use the appropriate standard SI prefix: nano-, micro-, milli-, kilo-, mega-, giga-, and so on.

sorry

step-by-step explanation:

sorry, but im pretty sure its a now that i look at it