Reaction that is first order with respect to a and b
a) is dependent on the concentration of a and b.
b) is dependent on the concentration of a
c) has smaller rate constants than first-order reactions regardless of reactant concentration
d) is independent of reactant concentration
e) is always faster than first-order reactions due to loss of concentration dependence.

a) is dependent on the concentration of A and B.

Explanation:

For a reaction:

A + B → C

That is first order with respect a and B have a rate of reaction (v) of:

v = k [A]¹ [B]¹ (1)

Where k is rate constant.

First order with respect a reactant means the exponent in the concentration of the reactant is 1.

Knowing this:

a) is dependent on the concentration of A and B.  TRUE. The rate of reaction depends of A and B.

b) is dependent on the concentration of A . FALSE. The reaction depends also of B.

c) has smaller rate constants than first-order reactions regardless of reactant concentration . FALSE. Rate constant depends of several factors as temperature, type of reaction, etc.

d) is independent of reactant concentration . FALSE. It depends of A and B.

e) is always faster than first-order reactions due to loss of concentration dependence. FALSE. When the concentration of reactants is decreasing, the rate of reaction will also decrease.

I hope it helps!