Answer : The correct option is, (a) Gold
Solution :

As we know that,

.................(1)
where,
= mass of metal = 10 g
= mass of added water = 30 g
= final temperature = ?
= temperature of metal =

= temperature of added water =

= specific heat of water =

= specific heat of metal
Now we have to calculate the final temperature for all the given metals.
(a) For gold : given,
= specific heat of metal =

![10g* 0.129J/g^oC* (T_(final)-65^oC)=-[30g* 4.184J/g^oC* (T_(final)-25^oC)]](https://img.qammunity.org/2017/formulas/chemistry/high-school/xbdgwvx5bci0qefioi72uttpqh6rw3y4iq.png)

Change in temperature of water =

(b) For silver : given,
= specific heat of metal =

![10g* 0.24J/g^oC* (T_(final)-65^oC)=-[30g* 4.184J/g^oC* (T_(final)-25^oC)]](https://img.qammunity.org/2017/formulas/chemistry/high-school/a4l4j555gvf5dr5x7otw9g9h04gf46tp62.png)

Change in temperature of water =

(c) For copper : given,
= specific heat of metal =

![10g* 0.385J/g^oC* (T_(final)-65^oC)=-[30g* 4.184J/g^oC* (T_(final)-25^oC)]](https://img.qammunity.org/2017/formulas/chemistry/high-school/5wchg8ty4ztk1fa4l9gaqktzje5is721ym.png)

Change in temperature of water =

(d) For aluminium : given,
= specific heat of metal =

![10g* 0.902J/g^oC* (T_(final)-65^oC)=-[30g* 4.184J/g^oC* (T_(final)-25^oC)]](https://img.qammunity.org/2017/formulas/chemistry/high-school/k9v32cj3chtpqdfhh2z2gpfnhwy1ul6fh5.png)

Change in temperature of water =

Therefore, the least temperature rise for water result in, Gold.