The simple interest rate per annum must be higher than the original 10% to achieve the same maturity amount after two years because compound interest results in more interest accumulation than simple interest.

Option 1 suggests that simple interest is the same as compound interest, which is incorrect in this scenario.

Option 3 proposes a growth rate of 11% which is higher than the required rate. This would result in a higher maturity amount, thus it is incorrect.

Similarly, Option 4 with a growth rate of 12% will result in an even higher maturity amount.

Option 2 is correct because a growth rate of 10.5% per annum as simple interest should generate the same maturity amount as a 10% per annum compounded annually over the same two-year period. In simple interest, the principal amount remains constant, hence the interest rate needs to be slightly higher to equal the compound interest.