What will come in the place of question (?) mark in following the question:
$1.5\times 8+?=2.1$

To find the value that comes in place of the question mark (?), we can write the given expression as an equation and solve for ? step-by-step.

The given equation is:
$1.5\times 8+?=2.1$

First, we perform the multiplication according to the order of operations (BODMAS/PEMDAS):
$1.5\times 8=12$

Now, substitute this value back into the equation:
$12+?=2.1$

To solve for ?, subtract 12 from both sides of the equation:
$?=2.1-12$

Subtracting 12 from 2.1 gives:
$?=-9.9$

Therefore, the value that should replace the question mark is -9.9, which corresponds to the first option.